Document:

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                                                                   EXHIBIT 10.20

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                              PETsMART.COM, INC.
                             AMENDED AND RESTATED
                           INVESTOR RIGHTS AGREEMENT
                                October 6, 1999

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                               TABLE OF CONTENTS

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1.   Certain Definitions............................................................................................   2

2.   Restrictions on Transferability................................................................................   4

3.   Restrictive Legend.............................................................................................   4

4.   Notice of Proposed Transfers...................................................................................   4

5.   Registration...................................................................................................   5

     5.1   Requested Registration...................................................................................   5
     5.2   Company Registration.....................................................................................   7
     5.3   Registration on Form S-3.................................................................................   8
     5.4   Subsequent Registration Rights...........................................................................   9
     5.5   Expenses of Registration.................................................................................   9
     5.6   Registration Procedures..................................................................................   9
     5.7   Indemnification..........................................................................................  11
     5.8   Information by Holder....................................................................................  13
     5.9   Rule 144 Reporting.......................................................................................  13
     5.10  Termination of Registration Rights.......................................................................  13

6.   Financial Information Rights...................................................................................  13

7.   Lockup Agreement...............................................................................................  15

8.   Right of First Refusal.........................................................................................  15

9.   Vesting of Employee Options....................................................................................  16

10.  Employment, Confidential Information and Invention Assignment Agreements......................................   16

11.  Transfer of Rights............................................................................................   16

12.  Waivers and Amendments........................................................................................   17

13.  Governing Law.................................................................................................   17

14.  Entire Agreement..............................................................................................   17

15.  Notices, etc..................................................................................................   17

16.  Counterparts..................................................................................................  187

17.  Titles and Subtitles..........................................................................................  187

18.  Successors and Assigns........................................................................................   18

19.  Aggregation of Stock..........................................................................................   18

20.  Entire Agreement..............................................................................................
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                                      -i-
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                              PETsMART.COM, INC.

                             AMENDED AND RESTATED

                           INVESTOR RIGHTS AGREEMENT

     This Amended and Restated Investor Rights Agreement (this "Agreement") is
made effective as of October 6, 1999, by and among PETsMART.com, Inc., a
Delaware corporation (the "Company"), the purchasers of the Company's Series D
Preferred Stock who are signatories to this Agreement (the "Purchasers") and the
Series A Purchasers (as defined herein), the Series B Purchasers (as defined
herein) and the Series C Purchasers (as defined herein).

                                    RECITALS

     A.   In connection with the issuance and sale of its Series A Preferred
Stock, its Series B Preferred Stock and its Series C Preferred Stock, the
Company entered into that certain Investor Rights Agreement dated May 12, 1999
(the "Original Agreement") with the purchasers of Series A Preferred Stock (the
"Series A Purchasers"), the purchasers of Series B Preferred Stock (the "Series
B Purchasers") and the purchasers of Series C Preferred Stock (the "Series C
Purchasers").

     B.   The Company and the Purchasers are parties to the Series D Preferred
Stock Purchase Agreement dated as of October 6, 1999 (the "Purchase Agreement"),
whereby the Company will sell, and the Purchasers will buy, Series D Preferred
Stock of the Company.

     C.   The obligations of the Company and the Purchasers under the Purchase
Agreement are conditioned, among other things, upon the execution and delivery
of this Agreement by the Company and the Purchasers.

     D.   Section 12 of the Original Agreement provides that the consent of the
Company and the holders of a majority of the Registrable Securities (as defined
in the Original Agreement), a majority of the holders of the Series A Preferred
Stock, a majority of the holders of the Series B Preferred Stock and a majority
of the holders of the Series C Preferred Stock (provided, that Section 8 of the
Original Agreement may be amended only with the written consent of the Company
and the Qualified Purchasers (as defined in the Original Agreement) representing
a majority of the Registrable Securities then held by all of the Qualified
Purchasers (as defined in the Original Agreement) is required to amend the
Original Agreement.

                                     -ii-

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     E.   The Company and the holders required to amend the Original Agreement
pursuant to Section 12 thereof now desire to and hereby amend and restate the
Original Agreement in its entirety as set forth below in order to add the
Purchasers as parties hereto and make certain changes to the Original Agreement.

                                   AGREEMENT

     NOW, THEREFORE, in consideration of the mutual promises and covenants
herein, the receipt and sufficiency of which are hereby acknowledged, the
parties hereto agree to amend and restate the Original Agreement in its entirety
and agree as follows:

     1.   Certain Definitions.  As used in this Agreement, the following terms
          -------------------
shall have the following respective meanings:

          "Change of Control" means the Company's sale or lease of all or
substantially all of its assets or the acquisition of the Company by another
entity by means of merger or consolidation resulting in the exchange of the
outstanding shares of the Company for securities or consideration issued, or
caused to be issued, by the acquiring corporation or its subsidiary, unless the
stockholders of the Company immediately prior to such transaction hold at least
50% of the voting power of the surviving corporation in such a transaction.

          "Commission" means the Securities and Exchange Commission or any other
federal agency at the time administering the Securities Act.

          "Conversion Stock" means the Company's Common Stock (i) issued or
issuable pursuant to conversion of the Preferred Stock and (ii) issued or
issuable upon exercise of warrants granted to idealab! Holdings, L.L.C.,
PETsMART, Inc. and Rodale Press, Inc.

          "Exchange Act" means the Securities Exchange Act of 1934, as amended,
or any similar federal rule or statute and the rules and regulations of the
Commission thereunder, all as the same shall be in effect at the time.

          "Holder" means (i) any Series A Investor, Series B Investor, Series C
Investor or Purchaser holding Registrable Securities and (ii) any person holding
Registrable Securities to whom rights have been transferred under this
Agreement, in accordance with Section 11 hereof.

          "Initiating Holders" means any Holder or Holders who, in the
aggregate, hold not less than 50% of the Registrable Securities then
outstanding.

          "IPO" shall mean the Company's initial public offering pursuant to an
effective registration statement under the Securities Act covering the offer and
sale of the Company's Common Stock.

          "Preferred Stock" shall mean the Company's Series A Preferred Stock,
Series B Preferred Stock and Series C Preferred Stock and Series D Preferred
Stock.

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          "Qualified Initial Public Offering" shall mean the Company's IPO with
gross proceeds to the Company of not less than $15 million and at a minimum
offering price of $9.35 per share.

          "Qualified Purchaser" shall mean (i) idealab! Holdings, L.L.C.,
PETsMART, Inc. and the Series B Purchasers and (ii) any person holding
Registrable Securities to whom rights have been transferred by idealab!
Holdings, L.L.C., PETsMART, Inc. or the Series B Purchasers under this
Agreement, in accordance with Section 11 hereof.

          "Registrable Securities" means (i) the Conversion Stock and (ii) any
Common Stock of the Company issued or issuable in respect of any of the
foregoing or upon any stock split, stock dividend, recapitalization or similar
event; provided, however, that securities shall only be treated as Registrable
Securities if and so long as (x) they have not been registered or sold to or
through a broker or dealer or underwriter in a public distribution or a public
securities transaction and (y) the registration rights with respect to such
securities have not terminated pursuant to Section 5.10.

          The terms "register," "registered" and "registration" refer to a
registration effected by preparing and filing a registration statement in
compliance with the Securities Act, and the declaration or ordering of the
effectiveness of such registration statement.

          "Registration Expenses" shall mean all expenses, except as otherwise
stated below, incurred by the Company in complying with Sections 5.1, 5.2 and
5.3 hereof, including, without limitation, all federal and state registration,
qualification and filing fees, printing expenses, escrow fees, fees and
disbursements of counsel for the Company, blue sky fees and expenses, the
expense of any special audits incident to or required by any such registration
(but excluding the compensation of regular employees of the Company which shall
be paid in any event by the Company).  Registration Expenses shall also include
the fees and disbursements for one special counsel to the selling stockholders
selected by a majority of such holders, not to exceed $15,000 per registration.

          "Restricted Securities" shall mean the securities of the Company
required to bear the legends set forth in Section 3 hereof.

          "Rule 144" and "Rule 145" shall mean Rules 144 and 145, respectively,
promulgated under the Securities Act, or any similar federal rules thereunder,
all as the same shall be in effect at the time.

          "Securities Act" shall mean the Securities Act of 1933, as amended, or
any similar federal rule or statute and the rules and regulations of the
Commission thereunder, all as the same shall be in effect at the time.

          "Selling Expenses" shall mean all underwriting discounts, selling
commissions and stock transfer taxes applicable to the securities registered by
the Holders and, except as set forth above, all fees and disbursements of
counsel for any Holder.

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     2.   Restrictions on Transferability.  The Preferred Stock, the Conversion
          -------------------------------
Stock and any other securities issued in respect of such stock upon any stock
split, stock dividend, recapitalization, merger, or similar event, shall not be
sold, assigned, transferred or pledged except upon the conditions specified in
this Agreement, which conditions are intended to ensure compliance with the
provisions of the Securities Act.  Each Holder or transferee will cause any
proposed purchaser, assignee, transferee, or pledgee of any such shares held by
the Holder or transferee to agree to take and hold such securities subject to
the restrictions and upon the conditions specified in this Agreement.

     3.   Restrictive Legend.  Each certificate representing the Preferred
          ------------------
Stock, the Conversion Stock or any other securities issued in respect of such
stock upon any stock split, stock dividend, recapitalization, merger, or similar
event, shall (unless otherwise permitted by the provisions of Section 4 below)
be stamped or otherwise imprinted with legends in substantially the following
form (in addition to any legends required by agreement or by applicable state
securities laws):

          THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE
          SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"). SUCH SECURITIES MAY
          NOT BE TRANSFERRED UNLESS A REGISTRATION STATEMENT UNDER THE ACT IS IN
          EFFECT AS TO SUCH TRANSFER OR IN THE OPINION OF COUNSEL FOR THE
          COMPANY, SUCH TRANSFER MAY BE MADE PURSUANT TO RULE 144 OR
          REGISTRATION UNDER THE ACT IS OTHERWISE UNNECESSARY IN ORDER FOR SUCH
          TRANSFER TO COMPLY WITH THE ACT.

          THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO A LOCKUP
          PERIOD OF UP TO 180 DAYS FOLLOWING THE EFFECTIVE DATE OF A
          REGISTRATION STATEMENT OF THE COMPANY FILED UNDER THE SECURITIES ACT
          OF 1933, AS AMENDED, AS SET FORTH IN AN AGREEMENT BETWEEN THE ISSUER
          AND THE ORIGINAL HOLDER OF THESE SHARES, A COPY OF WHICH MAY BE
          OBTAINED AT THE PRINCIPAL OFFICE OF THE ISSUER. SUCH LOCKUP PERIOD IS
          BINDING ON TRANSFEREES OF THESE SHARES.

          Each Holder consents to the Company making a notation on its records
and giving stop transfer instructions to any transfer agent of its capital stock
in order to implement the restrictions on transfer established in this
Agreement.

     4.   Notice of Proposed Transfers.  The holder of each certificate
          ----------------------------
representing Restricted Securities by acceptance thereof agrees to comply in all
respects with the provisions of this Section 4.  Without in any way limiting the
immediately preceding sentence, no sale,

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assignment, transfer or pledge of Restricted Securities shall be made by any
holder thereof to any person unless such person shall first agree in writing to
be bound by the restrictions of this Agreement. Prior to any proposed sale,
assignment, transfer or pledge of any Restricted Securities, unless there is in
effect a registration statement under the Securities Act covering the proposed
transfer, the holder thereof shall give written notice to the Company of such
holder's intention to effect such transfer, sale, assignment or pledge. Each
such notice shall describe the manner and circumstances of the proposed
transfer, sale, assignment or pledge in sufficient detail, and, if requested by
the Company, the holder shall also provide, at such holder's expense, a written
opinion of legal counsel who shall be, and whose legal opinion shall be,
reasonably satisfactory to the Company addressed to the Company, to the effect
that the proposed transfer of the Restricted Securities may be effected without
registration under the Securities Act, whereupon the holder of such Restricted
Securities shall be entitled to transfer such Restricted Securities in
accordance with the terms of the notice delivered by the holder to the Company;
provided, however, that the Company shall not request an opinion of counsel with
respect to (i) a transfer not involving a change in beneficial ownership or
involving an entity that is an affiliate (as such term is defined in Rule 405 of
the Securities Act) of a Holder, (ii) a transaction involving the distribution
without consideration of Restricted Securities by the holder to its constituent
partners or members in proportion to their ownership interests in the holder, or
(iii) a transaction involving the transfer without consideration of Restricted
Securities by an individual holder during such holder's lifetime by way of gift
or on death by will or intestacy. Each certificate evidencing the Restricted
Securities transferred as above provided shall bear, except if such transfer is
made pursuant to Rule 144, the appropriate restrictive legend set forth in
Section 3 above, except that such certificate shall not bear such restrictive
legend if in the opinion of counsel for such holder and counsel for the Company
such legend is not required in order to establish compliance with any provision
of the Securities Act. Notwithstanding the foregoing, each holder of Restricted
Securities agrees that it will not request that a transfer of the Restricted
Securities be made or that the legend set forth in Section 3 be removed from the
certificate representing the Restricted Securities, solely in reliance on Rule
144(k), if as a result thereof the Company would be rendered subject to the
reporting requirements of the Exchange Act.

     5.   Registration.
          ------------

          5.1  Requested Registration.
               ----------------------

               (a) Request for Registration.  In case the Company shall receive
                   ------------------------
from Initiating Holders a written request that the Company effect any
registration with respect to shares of Registrable Securities, the Company will:

                   (i)  promptly give written notice of the proposed
registration to all other Holders; and

                   (ii) as soon as practicable, use commercially reasonable
efforts to effect such registration as part of a firm commitment underwritten
public offering with underwriters reasonably acceptable to the Initiating
Holders and the Company (including,

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without limitation, appropriate qualification under applicable state securities
laws and appropriate compliance with applicable regulations issued under the
Securities Act and any other governmental requirements or regulations) as may be
so requested and as would permit or facilitate the sale and distribution of all
or such portion of such Registrable Securities as are specified in such request,
together with all or such portion of the Registrable Securities of any Holder or
Holders joining in such request by delivering a written notice to such effect to
the Company within twenty days after the date of such written notice from the
Company.

     Notwithstanding the foregoing, the Company shall not be obligated to take
any action to effect or complete any such registration pursuant to this Section
5.1:

                         (A) Prior to six months after the effective date of the
Company's first registered public offering of its Common Stock;

                         (B) Unless the requested registration would have an
aggregate offering price of all Registrable Securities sought to be registered
by all Holders, net of underwriting discounts and commissions, exceeding
$5,000,000;

                         (C) Following the filing of, and for 180 days
immediately following the effective date of, any registration statement
pertaining to securities of the Company (other than a registration of securities
in a Rule 145 transaction or with respect to an employee benefit plan), provided
that the Company is actively employing in good faith commercially reasonable
efforts to cause such registration statement to become effective;

                         (D) After the Company has effected two (2)
registrations pursuant to this Section 5.1(a) in which the Initiating Holders
were able to sell at least 50% of the Registrable Securities sought to be
included and such registrations have each been declared or ordered effective;

                         (E) If the Initiating Holders are able to request a
registration on Form S-3 pursuant to Section 5.3 hereof;

                         (F) Within twelve (12) months after the Company has
effected such a registration pursuant to this Section 5.1(a), and such
registration has been declared or ordered effective; or

                         (G) If the Company shall furnish to the Initiating
Holders a certificate signed by the President of the Company (i) giving notice
of its bona fide intention to effect the filing of a registration statement with
the Commission, or (ii) stating that in the good faith judgment of the Board of
Directors it would be seriously detrimental to the Company or its stockholders
for a registration statement to be filed in the near future. In such case, the
Company's obligation to use its commercially reasonable efforts to register,
qualify or comply under this Section 5.1(a) shall be deferred one or more times
for a period not to exceed 180 days from the receipt of the request to file such
registration by such Initiating Holder or Holders, provided that the Company may
not exercise this deferral right more than once per twelve (12) month period.

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     Subject to the foregoing clauses (A) through (G), the Company shall file a
registration statement covering the Registrable Securities so requested to be
registered as soon as practicable after receipt of the request or requests of
the Initiating Holders.

          (b) Underwriting.  In the event of a registration pursuant to Section
              ------------
5.1, the Company shall advise the Holders as part of the notice given pursuant
to Section 5.1(a)(i) that the right of any Holder to registration pursuant to
Section 5.1 shall be conditioned upon such Holder's participation in the
underwriting arrangements required by this Section 5.1, and the inclusion of
such Holder's Registrable Securities in the underwriting to the extent requested
shall be limited to the extent provided herein.

     The Company shall, together with all Holders proposing to distribute their
securities through such underwriting, enter into an underwriting agreement in
customary form with the managing underwriter selected for such underwriting by a
majority in interest of the Initiating Holders, but subject to the Company's
reasonable approval.  Notwithstanding any other provision of this Section 5.1,
if the managing underwriter determines that marketing factors require a
limitation of the number of shares to be underwritten, the managing underwriter
may limit the Registrable Securities to be included in such registration (i) in
the case of the Company's initial public offering, to zero, and (ii) in the case
of any other offering, to an amount no less than thirty-three percent (33%) of
all shares to be included in such offering.  The Company shall so advise all
Holders requesting to be included in the registration and underwriting, and the
number of shares of Registrable Securities that may be included in the
registration and underwriting shall be allocated among all Holders requesting to
be included in the registration and underwriting in proportion, as nearly as
practicable, to the respective amounts of Registrable Securities held by them at
the time of filing the registration statement.  No Registrable Securities
excluded from the underwriting by reason of the underwriter's marketing
limitation shall be included in such registration.  To facilitate the allocation
of shares in accordance with the above provisions, the Company or the
underwriters may round the number of shares allocated to any Holder to the
nearest 100 shares.  If any Holder of Registrable Securities disapproves of the
terms of the underwriting, such person may elect to withdraw therefrom by
written notice to the Company.

          5.2  Company Registration.(a) Notice of Registration.  If at any time
               --------------------     ----------------------
or from time to time the Company shall determine to register any of its equity
securities, either for its own account or the account of a Holder or other
holders, other than (i) a registration relating solely to employee benefit
plans, (ii) a registration relating solely to a Rule 145 transaction, or (iii) a
registration in which the only equity security being registered is Common Stock
issuable upon conversion of convertible debt securities which are also being
registered, the Company will:

                    (i)  promptly give to each Holder written notice thereof;
                         and

                    (ii) include in such registration (and any related
qualifications including compliance with Blue Sky laws), and in any underwriting
involved therein, all the

                                       7
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Registrable Securities specified in a written request or requests, made within
ten days after the date of such written notice from the Company, by any Holder.

          (b) Underwriting.  If the registration of which the Company gives
              ------------
notice is for a registered public offering involving an underwriting, the
Company shall so advise the Holders as a part of the written notice given
pursuant to Section 5.2(a)(i).  In such event, the right of any Holder to
registration pursuant to Section 5.2 shall be conditioned upon such Holder's
participation in such underwriting and the inclusion of Registrable Securities
in the underwriting shall be limited to the extent provided herein.

     All Holders proposing to distribute their securities through such
underwriting shall (together with the Company and the other Holders distributing
their securities through such underwriting) enter into an underwriting agreement
in customary form with the managing underwriter selected for such underwriting
by the Company.  Notwithstanding any other provision of this Section 5.2, if the
managing underwriter determines that marketing factors require a limitation of
the number of shares to be underwritten, the managing underwriter may limit in
whole or in part the Registrable Securities to be included in such registration.
The Company shall so advise all Holders requesting to be included in the
registration and underwriting, and the number of shares of Registrable
Securities that may be included in the registration and underwriting shall be
allocated among all the Holders requesting to be included in the registration
and underwriting in proportion, as nearly as practicable, to the respective
amounts of Registrable Securities held by them at the time of filing the
registration statement.  To facilitate the allocation of shares in accordance
with the above provisions, the Company or the underwriters may round the number
of shares allocated to any Holder to the nearest 100 shares.  If any Holder
disapproves of the terms of any such underwriting, such person may elect to
withdraw therefrom by written notice to the Company.

          (c) Right to Terminate Registration.  The Company shall have the right
              -------------------------------
to terminate or withdraw any registration initiated by it under this Section 5.2
prior to the effectiveness of such registration whether or not any Holder has
elected to include securities in such registration.

     5.3  Registration on Form S-3.  (a)  Request for Registration.  In
          ------------------------        ------------------------
case the Company shall receive from Initiating Holders a written request that
the Company file a registration statement on Form S-3 (or any successor form to
Form S-3) for a public offering of shares of the Registrable Securities the
aggregate price to the public of which, net of underwriting discounts and
commissions, would exceed $500,000, and the Company is a registrant entitled to
use Form S-3 to register the Registrable Securities for such an offering, the
Company shall use commercially reasonable efforts to cause such Registrable
Securities to be registered for the offering on such form and to cause such
Registrable Securities to be qualified in such jurisdictions as such Holder or
Holders may reasonably request; provided, however, that the Company shall not be
required to effect more than one registration pursuant to this Section 5.3 in
any twelve (12) month period. If such offer is to be an underwritten offer, the
underwriters must be acceptable to both the Initiating Holders and the Company.
The Company shall inform the other Holders of the proposed registration and
offer them the opportunity to

                                       8
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participate. In the event the registration is proposed to be part of a firm
commitment underwritten public offering, the substantive provisions of Section
5.1(b) shall be applicable to each such registration initiated under this
Section 5.3.

     (b)  Notwithstanding the foregoing, the Company shall not be obligated to
take any action pursuant to this Section 5.3:

          (i)   Following the filing of, and for 180 days immediately following
the effective date of, any registration statement pertaining to securities of
the Company (other than a registration of securities in a Rule 145 transaction
or with respect to an employee benefit plan), provided that the Company is
actively employing in good faith commercially reasonable efforts to cause such
registration statement to become effective;

          (ii)  Within twelve (12) months after the Company has effected such a
registration pursuant to this Section 5.3(a), and such registration has been
declared or ordered effective; or

          (iii) If the Company shall furnish to the Initiating Holders a
certificate signed by the President of the Company (i) giving notice of its bona
fide intention to effect the filing of a registration statement with the
Commission, or (ii) stating that, in the good faith judgment of the Board of
Directors, it would be seriously detrimental to the Company or its stockholders
for a registration statement to be filed in the near future, then the Company's
obligation to use its commercially reasonable efforts to file a registration
statement shall be deferred one or more times for a period not to exceed 180
days from the receipt of the request to file such registration by such
Initiating Holder or Holders, provided that the Company may not exercise this
deferral right more than once per twelve (12) month period.

     5.4  Subsequent Registration Rights. (a) Without the consent of any holder
          ------------------------------
of Registrable Securities hereunder, the Company may grant to any holder of
securities of the Company registration rights inferior to those granted
hereunder.

          (b) The Company shall not enter into any agreement granting any holder
or prospective holder of any securities of the Company registration rights
superior to or on a pari passu basis with the rights granted the Holders
hereunder without the written consent of the holders of a majority of the
Registrable Securities.

     5.5  Expenses of Registration. All Registration Expenses incurred in
          ------------------------
connection with (i) two (2) registrations pursuant to Section 5.1, (ii) all
registrations pursuant to Section 5.2, and (iii) all registrations pursuant to
Section 5.3, shall be borne by the Company. Notwithstanding the foregoing, in
the event that Initiating Holders cause the Company to begin a registration
pursuant to Section 5.1, and the request for such registration is subsequently
withdrawn by the Initiating Holders (unless the withdrawal is based upon
material adverse information concerning the Company of which the Initiating
Holders were not aware at the time of such request) or such registration is not
completed due to failure to meet the net proceeds requirement set forth in such
section or is otherwise not successfully completed due to no fault of the
Company, all Holders shall be deemed to have forfeited their right to one
registration under

                                       9
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Section 5.1 unless the Initiating Holders pay for, or reimburse the Company for,
the Registration Expenses incurred in connection with such withdrawn or
incomplete registration. Unless otherwise stated, all Selling Expenses relating
to securities registered on behalf of the Holders and all other registration
expenses shall be borne by the Holders of such securities pro rata on the basis
of the number of shares so registered or proposed to be so registered.

     5.6  Registration Procedures. In the case of each registration effected by
          -----------------------
the Company pursuant to this Agreement, the Company will keep each Holder
advised in writing as to the initiation of such registration and as to the
completion thereof. The Company will:

          (a) Prepare and file with the Commission a registration statement with
respect to such Registrable Securities and use its reasonable efforts to cause
such registration statement to become effective, and, upon the request of the
Holders of a majority of the Registrable Securities registered thereunder, keep
such registration statement effective for a period of up to 120 days or until
the distribution contemplated in the registration statement has been completed;
provided, however, that such 120-day period shall be extended for a period of
time equal to the period the Holders refrain from selling any securities
included in such registration at the request of an underwriter of Common Stock
(or other securities) of the Company.

          (b) Prepare and file with the Commission such amendments and
supplements to such registration statement and the prospectus used in connection
with such registration statement as may be necessary to comply with the
provisions of the Securities Act with respect to the disposition of all
securities covered by such registration statement.

          (c) Furnish such number of prospectuses (including preliminary
prospectuses) in conformity with the requirements of the Securities Act and
other documents as a Holder from time to time may reasonably request.

          (d) Notify each Holder of Registrable Securities covered by such
registration statement at any time when a prospectus relating thereto is
required to be delivered under the Securities Act of the happening of any event
as a result of which the prospectus included in such registration statement, as
then in effect, includes an untrue statement of a material fact or omits to
state a material fact required to be stated therein or necessary to make the
statements therein not misleading in the light of the circumstances then
existing.

          (e) Cause all such Registrable Securities registered pursuant
hereunder to be listed on each securities exchange or on the Nasdaq Stock
Market, as the case may be, on which similar securities issued by the Company
are then listed.

          (f) Provide a transfer agent and registrar for all Registrable
Securities registered pursuant hereunder and a CUSIP number for all such
Registrable Securities, in each case not later than the effective date of such
registration.

          (g) Use its reasonable efforts to cause such Registrable Securities
covered by a registration statement to be registered with or approved by such
other governmental

                                      10
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agencies or authorities as may be necessary to enable the seller or sellers
thereof to consummate the disposition of such Registrable Securities.

          (h) Furnish, at the request of any Holder requesting registration of
Registrable Securities pursuant to this Section 5, on the date that such
Registrable Securities are delivered to the underwriters for sale in connection
with a registration pursuant to this Section 5, if such securities are being
sold through underwriters, or, if such registration with respect to such
securities becomes effective, a letter, dated such date, from the independent
certified public accountants of the Company, in form and substance as is
customarily given by independent certified public accountants to underwriters in
an underwritten public offering, addressed to the underwriters, if any, and, if
required by the independent certified public accounts, an opinion, dated such
date, of the counsel representing the Company for the purposes of such
registration, in form and substance as is customarily given to underwriters in
an underwritten public offering, addressed to the underwriters, if any.

     5.7  Indemnification.(a)  The Company will indemnify each Holder, each of
          ---------------
its officers and directors and partners, and each person controlling such Holder
within the meaning of Section 15 of the Securities Act, with respect to which
registration has been effected pursuant to this Agreement, against all expenses,
claims, losses, damages or liabilities (or actions in respect thereof),
including any of the foregoing incurred in settlement of any litigation,
commenced or threatened, arising out of or based on any untrue statement (or
alleged untrue statement) of a material fact contained in any registration
statement, prospectus, offering circular or other document, or any amendment or
supplement thereto, incident to any such registration, or based on any omission
(or alleged omission) to state therein a material fact required to be stated
therein or necessary to make the statements therein, in light of the
circumstances in which they were made, not misleading, or any violation by the
Company of the Securities Act, the Exchange Act, state securities laws or any
rule or regulation promulgated under such laws applicable to the Company in
connection with any such registration, and the Company will reimburse each such
Holder, each of its officers and directors, and each person controlling such
Holder, for any legal and any other expenses reasonably incurred, as such
expenses are incurred, in connection with investigating, preparing or defending
any such claim, loss, damage, liability or action, provided that the Company
will not be liable in any such case to the extent that any such claim, loss,
damage, liability or expense arises out of or is based on any untrue statement
or omission or alleged untrue statement or omission, made in reliance upon and
in conformity with written information furnished to the Company by an instrument
duly executed by such Holder or controlling person, and stated to be
specifically for use therein.

          (b) Each Holder will, if Registrable Securities held by such Holder
are included in the securities as to which such registration is being effected,
indemnify the Company, each of its directors and officers, other holders of the
Company's securities covered by such registration statement, each person who
controls the Company within the meaning of Section 15 of the Securities Act, and
each other such Holder, each of its officers and directors and each person
controlling such Holder within the meaning of Section 15 of the Securities Act,
against all claims, losses, damages and liabilities (or actions in respect
thereof) arising out of or based on any untrue statement (or alleged untrue
statement) of a material fact contained in any such

                                      11
<PAGE>

registration statement, prospectus, offering circular or other document, or any
omission (or alleged omission) to state therein a material fact required to be
stated therein or necessary to make the statements therein not misleading, or
any violation by the Holder of the Securities Act, the Exchange Act, state
securities laws or any rule or regulation promulgated under such laws applicable
to the Holder, and will reimburse the Company, such other Holders, such
directors, officers, persons, underwriters or control persons for any legal or
any other expenses reasonably incurred, as such expenses are incurred, in
connection with investigating or defending any such claim, loss, damage,
liability or action, but in the case of the Company or the other Holders or
their officers, directors or controlling persons, only to the extent that such
untrue statement (or alleged untrue statement) or omission (or alleged omission)
is made in such registration statement, prospectus, offering circular or other
document in reliance upon and in conformity with written information furnished
to the Company by such Holder specifically for use in such registration
statement or prospectus. Notwithstanding the foregoing, the liability of each
Holder under this subsection 5.7(b) shall be limited in an amount equal to the
public offering price of the shares sold by such Holder, unless such liability
arises out of or is based on willful misconduct or fraud by such Holder.

          (c) Each party entitled to indemnification under this Section 5.7 (the
"Indemnified Party") shall give notice to the party required to provide
indemnification (the "Indemnifying Party") promptly after such Indemnified Party
has actual knowledge of any claim as to which indemnity may be sought, and shall
permit the Indemnifying Party to assume the defense of any such claim or any
litigation resulting therefrom, provided that counsel for the Indemnifying
Party, who shall conduct the defense of such claim or litigation, shall be
approved by the Indemnified Party (whose approval shall not unreasonably be
withheld), and the Indemnified Party may participate in such defense at such
party's expense, and provided further that the failure of any Indemnified Party
to give notice as provided herein shall not relieve the Indemnifying Party of
its obligations under this Agreement unless the failure to give such notice is
materially prejudicial to an Indemnifying Party's ability to defend such action
and provided further, that the Indemnifying Party shall not assume the defense
for matters as to which there is a conflict of interest or there are separate
and different defenses; provided, that the Indemnifying Party shall remain
liable for reasonable legal expenses of one counsel for the Indemnified Party.
No Indemnifying Party, in the defense of any such claim or litigation, shall,
except with the consent of each Indemnified Party (whose consent shall not be
unreasonably withheld), consent to entry of any judgment or enter into any
settlement which does not include as an unconditional term thereof the giving by
the claimant or plaintiff to such Indemnified Party of a release from all
liability in respect to such claim or litigation.

          (d) Notwithstanding the foregoing, to the extent that the provisions
on indemnification and contribution contained in the underwriting agreement
entered into in connection with the underwritten public offering are in conflict
with the foregoing provisions, the provisions in the underwriting agreement
shall control.

     5.8  Information by Holder.  The Holder or Holders of Registrable
          ---------------------
Securities included in any registration shall furnish to the Company such
information regarding such Holder or Holders, the Registrable Securities held by
them and the distribution proposed by such

                                      12
<PAGE>

Holder or Holders as the Company may reasonably request in writing and as shall
be required in connection with any registration referred to in this Agreement.

          5.9  Rule 144 Reporting.  With a view to making available the benefits
               ------------------
of certain rules and regulations of the Commission which may at any time permit
the sale of the Restricted Securities to the public without registration, after
such time as a public market exists for the Common Stock of the Company, the
Company shall use its best efforts to:

               (a) Make and keep public information available, as those terms
are understood and defined in Rule 144 under the Securities Act, at all times
after the effective date that the Company becomes subject to the reporting
requirements of the Securities Act or the Exchange Act;

               (b) File with the Commission in a timely manner all reports and
other documents required of the Company under the Securities Act and the
Exchange Act (at any time after it has become subject to such reporting
requirements); and

               (c) So long as a Holder owns any Restricted Securities, furnish
to the Holder forthwith upon request a written statement by the Company as to
its compliance with the reporting requirements of said Rule 144 (at any time
after 90 days after the effective date of the first registration statement filed
by the Company for an offering of its securities to the general public), a copy
of the most recent annual or quarterly report of the Company, and such other
reports and documents of the Company and other information in the possession of
or reasonably obtainable by the Company as the Holder may reasonably request in
availing itself of any rule or regulation of the Commission allowing the Holder
to sell any such securities without registration.

          5.10 Termination of Registration Rights.  The rights granted pursuant
               ----------------------------------
to Sections 5.1, 5.2 and 5.3 of this Agreement shall terminate as to any Holder
upon the earlier of (i) the date four (4) years after the effective date of the
Company's IPO and (ii) the date such Holder is able to immediately sell all
shares of Registrable Securities held or entitled to be held upon conversion by
such Holder under Rule 144 during any 90-day period.

     6.   Financial Information Rights(a) The Company will provide the following
          ----------------------------
documents to each Holder who continues to hold at least 300,000 shares of
Preferred Stock and/or Conversion Stock (as adjusted for recapitalizations,
stock combinations, stock dividends, stock splits and the like) (each such
Holder, a "Major Investor"):

               (i) As soon as practicable after the end of the fiscal year
ending December 31, 1999 and each fiscal year thereafter, and in any event
within ninety (90) days after the end of each such fiscal year, consolidated
balance sheets of the Company and its subsidiaries, if any, as of the end of
such fiscal year, and consolidated statements of operations and consolidated
statements of cash flows and stockholders' equity of the Company and its
subsidiaries, if any, for such year, prepared in accordance with generally
accepted accounting principles and setting forth in each case in comparative
form the figures for the previous fiscal year (except that no such comparative
data from the fiscal year ended December 31, 1998 need be provided), all in
reasonable detail and audited by independent public accountants of national

                                      13
<PAGE>

standing selected by the Company, and a capitalization table in reasonable
detail for such fiscal year;

                    (ii)  As soon as practicable after the end of the first,
second and third quarterly accounting periods in each fiscal year of the Company
and in any event within sixty (60) days thereafter, a consolidated balance sheet
of the Company and its subsidiaries, if any, as of the end of each such
quarterly period, and consolidated statements of operations and consolidated
statements of cash flows of the Company and its subsidiaries, if any, for such
period and for the current fiscal year to date, prepared in accordance with
generally accepted accounting principles (other than accompanying notes),
subject to changes resulting from year-end audit adjustments, in reasonable
detail and signed by the principal financial or accounting officer of the
Company, and a capitalization table in reasonable detail for such quarterly
period, and such other documents generally distributed or made available to the
Company's stockholders; provided, however, that the Company shall not be
obligated to provide information which the Board of Directors deems in good
faith to be proprietary or confidential; and

                    (iii) Such other documents generally distributed or made
available to the Company's stockholders; provided, however, that the Company
                                         --------  -------
shall not be obligated to provide information which the Board of Directors deems
in good faith to be proprietary or confidential.

               (b)  For purposes of determining the minimum holdings pursuant to
this Section 6, any Holder which is a partnership or limited liability company
shall be deemed to hold any Preferred Stock originally purchased by such Holder
and subsequently distributed to constituent partners or members of such Holder,
but which have not been resold by such partners or members. If the partnership
or limited liability company is still in existence, the Company may satisfy any
obligation to distribute reports to individual partners of the partnership or
members of a limited liability company by delivering a single copy of each
report to the partnership or limited liability company as agent for the
constituent partners or members.

               (c)  Each Holder or transferee of rights under this Section 6
acknowledges and agrees that any information obtained pursuant to this Section 6
which may be considered nonpublic information will be maintained in confidence
by such Holder or transferee and will not be utilized by such Holder or
transferee in connection with purchases or sales of the Company's securities
except in compliance with applicable state and Federal securities laws.

               (d)  The covenants of the Company set forth in this Section 6
shall terminate and be of no further force or effect upon the earlier to occur
of (i) the closing of the IPO; or (ii) a Change of Control of the Company.

     7.   Lockup Agreement.  Each Holder and transferee hereby agrees that, in
          ----------------
connection with any registration of any securities of the Company under the
Securities Act for the account of the Company, if so requested by any
representative of the underwriters (the "Managing Underwriter"), such Holder or
transferee shall not sell or otherwise transfer any securities of the Company
during the period specified by the Company's Board of Directors at the request
of the Managing Underwriter (the "Market Standoff Period"), with such period not
to

                                      14
<PAGE>

exceed 180 days following the effective date of a registration statement of the
Company filed under the Securities Act. The Company may impose stop-transfer
instructions with respect to securities subject to the foregoing restrictions
until the end of such Market Standoff Period. The Company shall use commercially
reasonable efforts to place similar contractual lockup restrictions on all
capital stock issued now or hereafter to officers, directors, employees and
consultants of the Company and holders of registration rights with respect to
capital stock of the Company.

     8. Right of First Refusal.
        ----------------------

          (a) The Company hereby grants to the Qualified Purchasers the right of
first refusal to purchase its Pro Rata Share of New Securities (as defined in
this Section 8) which the Company may, from time to time, propose to sell and
issue.  A "Pro Rata Share," for purposes of this right of first refusal, equals
the proportion that the total number of shares of Common Stock then held by such
Qualified Purchaser plus the number of shares of Common Stock issuable upon
conversion of the Preferred Stock then held by such Qualified Purchaser bears to
the sum of the total number of shares of Common Stock then outstanding plus the
number of shares of Common Stock issuable upon exercise or conversion of all
then outstanding securities exercisable for or convertible into, directly or
indirectly, Common Stock.

          (b) Except as set forth below, "New Securities" shall mean any shares
of capital stock of the Company, including Common Stock and any series of
preferred stock, whether now authorized or not, and rights, options or warrants
to purchase said shares of Common Stock or preferred stock, and securities of
any type whatsoever that are, or may become, convertible into or exchangeable
for said shares of Common Stock or preferred stock.  Notwithstanding the
foregoing, "New Securities" does not include stock issued and issuable: (i)
upon conversion of shares of Preferred Stock; (ii) to employees, consultants, or
directors pursuant to stock option, stock grant, stock purchase, or similar
plans and arrangements approved by the Board of Directors; (iii) to equipment
lessors, banks financial institutions or similar entities in a transaction
approved the Board of Directors, the principle purpose of which is other than
the raising of capital; (iv) as a dividend or other distribution; (v) in the
Company's IPO; (vi) in a merger or acquisition that is approved by the Board of
Directors; (vii) pursuant to any transaction approved by the Board of Directors
primarily for the purpose of (A) joint ventures, technology licensing or
research and development activities, (B) distribution or manufacture of the
Company's products or services, or (C) any other transactions involving
corporate partners that are primarily for purposes other than raising capital;
provided that such transaction(s) include an agreement regarding such
relationship that is entered into at the same time as the issuance of the New
Securities; (viii) if the holders of a majority of the then outstanding shares
of Series A Preferred Stock and Series B Preferred Stock, voting separately,
agree in writing that such shares shall not constitute New Securities; or (ix)
upon exercise or conversion of securities with respect to which the Qualified
Purchasers previously had an opportunity to exercise the right of first refusal
pursuant to this Section 8.

          (c) In the event the Company proposes to undertake an issuance of New
Securities, it shall give each Qualified Purchaser written notice of its
intention, describing

                                      15
<PAGE>

the amount and type of New Securities, and the price and terms upon which the
Company proposes to issue the same. Each Qualified Purchaser shall have ten (10)
days from the date of receipt of any such notice to agree to purchase up to its
respective Pro Rata Share of such New Securities for the price and upon the
terms specified in the notice by giving written notice to the Company and
stating therein the quantity of New Securities to be purchased.

          (d) Beginning ten (10) days after the notice given pursuant to Section
8(c) above, the Company shall have 180 days to sell the New Securities not
elected or eligible to be purchased by Qualified Purchasers at the price and
upon the terms no more favorable to the purchasers of such securities than
specified in the Company's notice.  In the event the Company has not sold all of
the New Securities within said 180 day period, the Company shall not thereafter
issue or sell any New Securities without first offering such securities in the
manner provided above.

          (e) The provisions of this Section 8 will terminate and be of no
further force or effect upon the earlier to occur of: (i)  the closing of the
Company's IPO, or (ii) immediately prior to a Change of Control.

     9.   Vesting of Employee Options.  Unless otherwise agreed to by a majority
          ---------------------------
of the members of the Company's Board of Directors who are not then employees of
the Company, after the date hereof, options granted to employees of the Company
under the Company's 1999 Employee Stock Plan or other approved stock plans will
vest, until the option holder's employment with or service to the Company
terminates, on terms no more favorable to the employee than the following:
Twenty percent (20%) of such shares shall vest immediately upon employment and
five percent (5%) of such shares shall vest at the end of each quarter
thereafter.

     10.  Employment, Confidential Information and Invention Assignment
          -------------------------------------------------------------
Agreements.  The Company will maintain a policy requiring each person now or
----------
hereafter employed by it or any subsidiary with access to confidential
information to enter into an Employment, Confidential Information and Invention
Assignment Agreement substantially in a form approved by the Board of Directors.

     11.  Transfer of Rights.  The rights granted under Sections 5, 6 and 8 of
          ------------------
this Agreement may be assigned to any transferee or assignee, other than a
competitor or potential competitor of the Company or PETsMART (as determined in
good faith by the Company's Board of Directors), in connection with any transfer
or assignment of Registrable Securities by the Holder, provided that: (i) such
transfer is otherwise effected in accordance with applicable securities laws and
the terms of this Agreement; (ii) such assignee or transferee would be a Major
Investor immediately following such transfer or assignment, (iii) written notice
is promptly given to the Company and (iv) such transferee or assignee agrees to
be bound by the provisions of this Agreement.  Notwithstanding the foregoing,
the rights granted to the Holders hereunder may be assigned without compliance
with item (ii) above to (a) any constituent partner or member of a Holder which
is a partnership or limited liability company, or (b) any then affiliate (as
such term is defined in Rule 405 of the Securities Act) of a Holder.

                                      16
<PAGE>

     12.  Waivers and Amendments.  Except as otherwise provided herein,
          ----------------------
additional parties may be added to this Agreement, any provision of this
Agreement may be amended or the observance thereof may be waived (either
generally or in a particular instance and either retroactively or
prospectively), only with the written consent of the Company and the Holders of
a majority of the Registrable Securities then outstanding, a majority of the
holders of the Series A Preferred Stock, a majority of the holders of the Series
B Preferred Stock, a majority of the holders of the Series C Preferred Stock and
a majority of the holders of the Series D Preferred Stock.  Notwithstanding the
foregoing, Section 8 may be amended only with the written consent of the Company
and the Qualified Purchasers representing a majority of the Registrable
Securities then held by all of the Qualified Purchasers.  Any amendment or
waiver effected in accordance with Section 5.4 or Section 12, as applicable,
shall be binding upon each Purchaser, Holder of Registrable Securities at the
time outstanding, each future holder of any of such securities, and the Company.

     13.  Governing Law.  This Agreement shall be governed in all respects by
          -------------
the internal laws of the State of California without regard to conflict of laws
provisions.

     14.  Entire Agreement.  This Agreement constitutes the full and entire
          ----------------
understanding and Agreement among the parties regarding the matters set forth
herein.  Except as otherwise expressly provided herein, the provisions hereof
shall inure to the benefit of, and be binding upon, the successors, assigns,
heirs, executors and administrators of the parties hereto.

     15.  Notices, etc.  All notices and other communications required or
          ------------
permitted hereunder shall be in writing and shall be mailed by registered or
certified mail, postage prepaid, or otherwise delivered by facsimile
transmission, by hand or by messenger, addressed:

          (a) if to a Holder, at such Holder's address as set forth in Exhibit
A, or at such other address as such Holder shall have furnished to the Company.

          (b)  if to the Company, to:

               130 West Union Street
               Pasadena, California 91103
               Attn: Tom McGovern
               Fax:  (626) 535-2701

               or at such other address as the Company shall have furnished to
the Holders, with a copy to:

               Strategic Law Partners, LLP
               333 S. Grand Avenue
               Suite 3950
               Los Angeles, California  90071
               Attn: Bradley D. Schwartz, Esq.
               Fax:  (213) 621-0982

                                      17
<PAGE>

          Each such notice or other communication shall for all purposes of this
Agreement be treated as effective or having been given when delivered if
delivered personally, if sent by facsimile, the first business day after the
date of confirmation that the facsimile has been successfully transmitted to the
facsimile number for the party notified, or, if sent by mail, at the earlier of
its receipt or 72 hours after the same has been deposited in a regularly
maintained receptacle for the deposit of the United States mail, addressed and
mailed as aforesaid.

     16.  Counterparts.  This Agreement may be executed in any number of
          ------------
counterparts, each of which shall be an original and all of which together shall
constitute one instrument.

     17.  Titles and Subtitles.  The titles and subtitles used in this Agreement
          --------------------
are used for convenience only and are not to be considered in construing or
interpreting this Agreement.

     18.  Successors and Assigns.  Except as otherwise expressly provided
          ----------------------
herein, the provisions hereof shall inure to the benefit of, and be binding
upon, the successors, assigns, heirs, executors and administrators of the
parties hereto.

     19.  Aggregation of Stock.  For the purpose of determining the availability
          --------------------
of any rights hereunder, any shares of Series B Preferred Stock, or Common Stock
into which such Series B Preferred Stock is converted, held by entities which
control, are controlled by or are under common control with another entity shall
be aggregated.

     20.  Entire Agreement.  This Agreement constitutes the full and entire
          ----------------
understanding between the parties with regard to the subject matter hereof.  The
Original Agreement is hereby amended and restated in its entirety by this
Agreement, and the Company and the parties hereto agree that this Agreement
shall supersede and replace the rights and obligations of the parties and the
Company under the Original Agreement.

                  [Remainder of page intentionally left blank]

                                      18

<PAGE>

     IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of
the date first set forth above.

     "COMPANY"

     PETsMART.COM, INC.

        /s/ Tom McGovern, Jr.
     ----------------------------
     Tom McGovern, Jr.
     President

     "SERIES A PURCHASER"

     PETsMART, INC.

     By:   /s/ Phillip L. Francis
         ------------------------
     Philip L. Francis
     President and Chief Executive Officer

     "SERIES B PURCHASERS"

     IDEALAB! CAPITAL PARTNERS I-A, L.P.

      /s/ William S. Elkus
     ----------------------------
     William S. Elkus,
     Managing Member, idealab! Capital Management, I, LLC,
     General Partner of idealab! Capital Partners I-A, L.P.

                                      1
<PAGE>

     IDEALAB! CAPITAL PARTNERS I-B, L.P.

        /s/ William S. Elkus
     ----------------------------
     William S. Elkus,
     Managing Member, idealab! Capital Management, I, LLC,
     General Partner of idealab! Capital Partners I-B, L.P.

     GLOBAL RETAIL PARTNERS, L.P.
     BY: GLOBAL RETAIL PARTNERS, INC.
          General Partner

     By: /s/ Steven E. Lebow
        -------------------------
     Name: Steven E. Lepow
          -----------------------
     Title: Chairman
           ----------------------

     DLJ DIVERSIFIED PARTNERS, L.P.
     BY: DLJ DIVERSIFIED PARTNERS, INC.
          General Partner

     By: /s/ Steven E. Lebow
        -------------------------
     Name: Steven E. Lebow
          -----------------------
     Title: Chairman
           ----------------------

     DLJ DIVERSIFIED PARTNERS-A, L.P.
     BY: DLJ DIVERSIFIED PARTNERS, INC.
          General Partner

     By: /s/ Steven E. Lebow
        -------------------------
     Name: Steven E. Lebow
          -----------------------
     Title: Chairman
           ----------------------

                                       2
<PAGE>

     GRP PARTNERS, L.P.
     BY: GLOBAL RETAIL PARTNERS, INC.
          General Partner

     By: /s/ Steven E. Lebow
        ------------------------
     Name: Steven E. Lebow
          ----------------------
     Title: Chairman
           ---------------------

     GLOBAL RETAIL PARTNERS FUNDING, INC.

     By: /s/ Osamu R. Watanabe
        ------------------------
     Name: Osamu R. Watanabe
          ----------------------
     Title: Vice President
            --------------------

     DLJ ESC II L.P.
     BY: DLJ LBO PLANS MANAGEMENT CORPORATION
          General Partner

     By: /s/ Osamu R. Watanabe
        ------------------------
     Name: Osamu R. Watanabe
          ----------------------
     Title: Vice President
            --------------------

     "SERIES C PURCHASERS"

     IDEALAB! HOLDINGS, L.L.C.

     By: /s/ Marcia Goodstein
        ------------------------
     Name: Marcia Goodstein
          ----------------------
     Title: Secretary
            --------------------

                                      3
<PAGE>

     "SERIES D PURCHASERS"

     PETsMART, INC.

      /s/ Philip L. Francis
     ---------------------------
     Philip L. Francis
     President and Chief Executive Officer

     IDEALAB! CAPITAL PARTNERS I-A, L.P.

      /s/ William S. Elkus
     ---------------------------
     William S. Elkus,
     Managing Member, idealab! Capital Management, I, LLC,
     General Partner of idealab! Capital Partners I-A, L.P.

     IDEALAB! CAPITAL PARTNERS I-B, L.P.

      /s/ William S. Elkus
     ---------------------------
     William S. Elkus,
     Managing Member, idealab! Capital Management, I, LLC,
     General Partner of idealab! Capital Partners I-B, L.P.

     SIMBA, LLC

     By: /s/ Carina Schalvach
        ------------------------
     Name: Carina Schalvach
          ----------------------
     Title:_____________________

                                      4
<PAGE>

     WS INVESTMENT COMPANY  99B

     By: /s/ Marin W. Korman
        ------------------------
     Name: Marin W. Korman
          ----------------------
     Title: Member
           ---------------------

      /s/ Larry Sonsini
     ---------------------------
     LARRY SONSINI

      /s/ Martin W. Korman
     ---------------------------
     MARTIN W. KORMAN

      /s/ Tom McGovern, Jr.
     ---------------------------
     TOM MCGOVERN, JR.

      /s/ Michael Houlahan
     ---------------------------
     MICHAEL HOULAHAN

     GLOBAL RETAIL PARTNERS, L.P.
     BY: GLOBAL RETAIL PARTNERS, INC.
          General Partner

     By: /s/ Steven E. Lebow
        ------------------------
     Name: Steven E. Lebow
          ----------------------
     Title: Chairman
           ---------------------

     DLJ DIVERSIFIED PARTNERS, L.P.
     BY: DLJ DIVERSIFIED PARTNERS, INC.
          General Partner

     By: /s/ Steven E. Lebow
        ------------------------
     Name: Steven E. Lebow
          ----------------------
     Title: Chairman
           ---------------------

                                       5
<PAGE>

     DLJ DIVERSIFIED PARTNERS-A, L.P.
     BY: DLJ DIVERSIFIED PARTNERS, INC.
          General Partner

     By: /s/ Steven E. Lebow
        ------------------------
     Name: Steven E. Lebow
          ----------------------
     Title: Chairman
           ---------------------

     GRP PARTNERS, L.P.
     BY: GLOBAL RETAIL PARTNERS, INC.
          General Partner

     By: /s/ Steven E. Lebow
        ------------------------
     Name: Steven E. Lebow
          ----------------------
     Title: Chairman
           ---------------------

     GLOBAL RETAIL PARTNERS FUNDING, INC.

     By: /s/ Osamu R. Watanabe
        ------------------------
     Name: Osamu R. Watanabe
          ----------------------
     Title: Vice President
           ---------------------

     DLJ ESC II L.P.
     BY: DLJ LBO PLANS MANAGEMENT CORPORATION
          General Partner

     By: /s/ Osamu R. Watanabe
        ------------------------
     Name: Osamu R. Watanabe
          ----------------------
     Title: Vice President
           ---------------------

                                      6
<PAGE>

     IDEALAB! HOLDINGS, L.L.C.

     By: /s/ Marcia Goodstein
        -----------------------
     Name: Marcia Goodstein
          ---------------------
     Title: Secretary
           --------------------

      /s/ Bradley D. Schwartz
     --------------------------
     BRADLEY D. SCHWARTZ

      /s/ James Baer
     --------------------------
     JAMES K. BAER

     BIG DOG USA, INC.

     By: /s/ AF
        -----------------------
     Name: Andrew Feshbach
          ---------------------
     Title: CEO
           --------------------

      /s/ AF
     --------------------------
     ANDREW FESHBACH

      /s/ Anthony Wall
     --------------------------
     ANTHONY WALL

      /s/ Andrew Wadhams
     --------------------------
     ANDREW WADHAMS

      /s/ Douglas Nilsen
     --------------------------
     DOUGLAS NILSEN

                                       7
<PAGE>

      /s/ Roberta Morris
     ---------------------------------------
     ROBERTA MORRIS

      /s/ Jeffrey Cowen
     ---------------------------------------
     JEFFREY COWEN

      /s/ David Wolf
      --------------------------------------
     DAVID WOLF

      /s/ Siska Buitenman
     ---------------------------------------
     SISKA BUITENMAN

     SK PRIVATE INVESTMENT FUND - SERIES B

     By: /s/ Thomas H. Kennedy
        ------------------------------------
     Name:   Thomas H. Kennedy
          ----------------------------------
     Title:  Member, Investment Committee
           ---------------------------------

                                       8<PAGE>

                                                                   EXHIBIT 10.21

EXCEPT AS OTHERWISE PROVIDED HEREIN, THIS WARRANT MAY NOT BE TRANSFERRED AND THE
SHARES OF COMMON STOCK ISSUABLE HEREUNDER HAVE NOT BEEN REGISTERED UNDER THE
SECURITIES ACT OF 1933, AS AMENDED, OR ANY APPLICABLE STATE SECURITIES LAWS, AND
MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED, HYPOTHECATED OR OTHERWISE
TRANSFERRED IN THE ABSENCE OF A REGISTRATION STATEMENT IN EFFECT WITH RESPECT TO
THE SHARES UNDER SUCH ACT AND APPLICABLE LAWS OR SOME OTHER EXEMPTION FROM THE
REGISTRATION REQUIREMENTS OF SUCH ACT AND APPLICABLE LAWS OR AN OPINION OF
COUNSEL SATISFACTORY TO THE COMPANY THAT REGISTRATION, QUALIFICATION OR OTHER
SUCH ACTIONS ARE NOT REQUIRED UNDER ANY SUCH LAWS. THE OFFERING OF THIS SECURITY
HAS NOT BEEN REVIEWED OR APPROVED BY ANY STATE'S SECURITIES ADMINISTRATOR.

No. 4                                      Warrant to Purchase 830,000 Shares of
                                           Common Stock (subject to adjustment)

                              WARRANT TO PURCHASE
                                 COMMON STOCK
                                      of
                              PETsMART.COM, INC.

     THIS CERTIFIES THAT, for value received, Big Dog USA, Inc. or its Permitted
Transferee ("Holder") is entitled, subject to the terms set forth below, to
purchase from PETsMART.com, Inc., a Delaware corporation (the "Company"), Eight
Hundred Thirty Thousand (830,000) shares of the Common Stock (the "Common
Stock") of the Company, as of the date hereof (the "Warrant Issue Date"), upon
surrender hereof, at the principal office of the company referred to below, with
the subscription form attached hereto duly executed, and simultaneous payment
therefor in lawful money of the United States or otherwise as hereinafter
provided, at the Exercise Price as set forth in Section 2 below. The number,
                                                ---------
character and Exercise Price of such shares of Common Stock are subject to
adjustment as provided below. The term "Warrant" as used herein shall include
this Warrant, for the Common Stock of the Company, and any warrants delivered in
substitution or exchange therefor as provided herein.
<PAGE>

     This Warrant is issued in connection with the transactions described in
that certain Strategic Relationship Agreement between the Company, Holder and
Big Dogs Holdings, Inc., of even date herewith (the "SRA"). The exercise of
this Warrant is subject to certain provisions of the SRA. In accordance with
Section 11.2, 15 and 26.6 of the SRA, which sections are specifically
-------------------------
incorporated herein by this reference, this Warrant may be (i) amended by the
Company and the number of shares into which this Warrant is exercisable may be
reduced by the Company based upon the performance goals set forth therein or
(ii) cancelled.

     1.   Term of Warrant.  Subject to the terms and conditions set forth
          ---------------
herein, this Warrant shall be exercisable, in whole or in part, during the term
commencing on the Warrant Issue Date and ending at the earlier of (i) three
years from the date of a firm commitment underwritten initial public offering of
capital stock by the Company ("IPO"), and (ii) 5:00 p.m., Pacific time, on the
fifth anniversary of the date of this Warrant Issue Date, and shall be void
thereafter.

     2.   Exercise Price.  The Exercise Price at which this Warrant may be
          --------------
exercised shall be 205,000 shares of Common Stock at $8.88 per share, 205,000
shares of Common Stock at $17.75 per share, 210,000 shares of Common Stock at
$26.63 per share and 210,000 shares of Common Stock at $35.50 per share (each
such group of shares of Common Stock that are purchasable upon exercise of this
Warrant at a particular price level is referred to as a "Tranche"), each as
adjusted from time to time pursuant to Section 11 hereof.
                                       ----------

     3.   Exercise of Warrant.
          -------------------

          (a)  The purchase rights represented by this Warrant are exercisable
     by the Holder in whole or in part, at any time, or from time to time,
     during the term hereof as described in Section 1 above, by the surrender of
                                            ---------
     this Warrant and the Notice of Exercise annexed hereto duly completed and
     executed on behalf of the Holder, at the office of the Company (or such
     other office or agency of the Company as it may designate by notice in
     writing to the Holder at the address of the Holder appearing on the books
     of the Company), upon payment:

               (i)  in cash or by check acceptable to the Company,

                                       2
<PAGE>

               (ii)  by cancellation by the Holder of indebtedness or other
          obligations of the Company to the Holder (at the option of the
          Company), or

               (iii) by a combination of (i) and (ii) (at the option of the
          Company), of the purchase price of the shares to be purchased.

          (b)  This Warrant shall be deemed to have been exercised immediately
     prior to the close of business on the date of its surrender for exercise as
     provided above, and the person entitled to receive the shares of Common
     Stock issuable upon such exercise shall be treated for all purposes as the
     holder of record of such shares as of the close of business on such date.
     As promptly as practicable on or after such date and in any event within
     ten (10) business days thereafter, the Company at its expense shall issue
     and deliver to the person or persons entitled to receive the same a
     certificate or certificates for the number of shares issuable upon such
     exercise.

          (c)  Notwithstanding any provisions herein to the contrary, if the
     fair market value of one share of Common Stock is greater than the Exercise
     Price of a particular Tranche (at the date of calculation as set forth
     below), in lieu of exercising this Warrant with respect to such Tranche for
     cash, the Holder or the Company may require that the Holder receive shares
     equal to the value (as determined below) of this Warrant with respect to
     such Tranche(s) being cancelled (or the portion thereof being cancelled) by
     surrender of this Warrant at the principal office of the Company together
     with the properly endorsed Notice of Exercise and notice of such election
     in which event the company shall issue to the Holder a number of shares of
     Common Stock computed using the following formula:

                                  X = Y (A-B)
                                      -------
                                         A

     Where: X = the number of shares of Common Stock to be issued to the Holder

            Y = the number of shares of Common Stock purchasable under a
                particular Tranche of the Warrant or, if only a portion of a
                Tranche of the Warrant is being exercised, the portion of the

                                       3
<PAGE>

                particular Tranche of the Warrant being cancelled (at the date
                of such calculation)

            A = the fair market value of one share of the Company's Common Stock
                (at the date of such calculation)

            B = Exercise Price for a particular Tranche (as adjusted to the date
                of such calculation)

For purposes of the above calculation, fair market value of one share of Common
Stock shall be determined by the Company's Board of Directors in good faith;
provided, however, that where there exists a public market for the Company's
Common Stock at the time of such exercise, the fair market value per share shall
be the product of (i) the average of the closing bid and asked prices of the
Common Stock quoted in the Over-The-Counter Market Summary or the last reported
sale price of the Common Stock or the closing price quoted on the NASDAQ
National Market or on any exchange on which the Common Stock is listed,
whichever is applicable, as published in the Western Edition of The Wall Street
Journal for the five (5) trading days prior to the date of determination of fair
market value and (ii) the number of shares of Common Stock at the time of such
exercise. Notwithstanding the foregoing, in the event the Warrant is exercised
in connection with the Company's initial public offering of Common Stock, the
fair market value per share shall be the per share offering price to the public
of the Company's initial public offering.

     4.   No Fractional Shares or Scrip.  No fractional shares or scrip
          -----------------------------
representing fractional shares shall be issued upon the exercise of this
Warrant. In lieu of any fractional share to which the Holder would otherwise be
entitled, the Company shall make a cash payment equal to the Exercise Price
multiplied by such fraction.

     5.   Replacement of Warrant.  On receipt of evidence reasonably
          ----------------------
satisfactory to the Company of the loss, theft, destruction or mutilation of
this Warrant and, in the case of loss, theft or destruction, on delivery of any
indemnity agreement reasonably satisfactory in form and substance to the Company
or, in the case of mutilation, on surrender and cancellation of this Warrant,
the Company at its expense shall execute and deliver, in lieu of this Warrant, a
new warrant of like tenor and amount.

                                       4
<PAGE>

     6.   Rights of Stockholders.  Subject to Sections 9 and 11 of this Warrant,
          ----------------------              -----------------
the Holder shall not be entitled to vote or receive dividends or be deemed the
holder of Common Stock or any other securities of the Company that may at any
time be issuable on the exercise hereof for any purpose, nor shall anything
contained herein be construed to confer upon the Holder, as such, any of the
rights of a stockholder of the Company or any right to vote for the election of
directors or upon any matter submitted to stockholders at any meeting thereof,
or to give or withhold consent to any corporate action (whether upon any
recapitalization, issuance of stock, reclassification of stock, change of par
value, or change of stock to no par value, consolidation, merger, conveyance, or
otherwise) or to receive notice of meeting, or to receive dividends or
subscription rights or otherwise until the Warrant shall have been exercised as
provided herein.

     7.   Transfer of Warrant.
          --------------------

          (a)  Warrant Register.  The Company will maintain a register (the
               ---------------
     "Warrant Register") containing the names and addresses of the Holder or
     Holders. Any Holder of this Warrant or any portion thereof may change its
     address as shown on the Warrant Register by written notice to the Company
     requesting such change. Any notice or written communication required or
     permitted to be given to the Holder may be delivered or given by mail to
     such Holder as shown on the Warrant Register and at the address shown on
     the Warrant Register. Until this Warrant is transferred on the Warrant
     Register of the Company, the Company may treat the Holder as shown on the
     Warrant Register as the absolute owner of this Warrant for all purposes,
     notwithstanding any notice to the contrary.

          (b)  Warrant Agent.  The Company may, by written notice to the Holder,
               -------------
     appoint an agent for the purpose of maintaining the Warrant Register
     referred to in Section 7(a) above, issuing the Common Stock then issuable
                    ------------
     upon the exercise of this Warrant, exchanging this Warrant, replacing this
     Warrant, or any or all of the foregoing. Thereafter any such registration,
     issuance, exchange, or replacement, as the case may be, shall be made at
     the office of such agent.

          (c)  Transferability and Nonnegotiability of Warrant.  This Warrant
               -----------------------------------------------
     may not be transferred or assigned in whole or in part except as set forth
     below. Except as set forth below, upon the transfer of this Warrant, this
     Warrant shall be null and void ab initio. Notwithstanding the foregoing,(i)
                                    ---------

                                       5
<PAGE>

     this Warrant may be transferred to any company merging with or acquiring
     substantially all of the assets of Holder subject to Section 26.6 of the
     SRA, and (ii) warrants to purchase up to 70,000 shares may be transferred
     to employees of Holder other than Andrew Feshbach or Fred Kayne (a
     "Permitted Transferee") and in each instance after compliance with all
                                                  -----
     applicable federal and state securities laws by the transferor and the
     transferee (including the delivery of investment representation letters and
     legal opinions reasonably satisfactory to the Company, if such are
     requested by the Company). Subject to the provisions of this Warrant
     described herein and compliance with the Securities Act of 1933, as amended
     (the "Act"), title to this Warrant may be transferred by endorsement to a
     Permitted Transferee (by the Holder executing the Assignment Form annexed
     hereto) and delivery in the same manner as a negotiable instrument
     transferable by endorsement and delivery.

          (d)  Exchange of Warrant Upon a Transfer.  On surrender of this
               -----------------------------------
     Warrant for exchange, properly endorsed on the Assignment Form and subject
     to the provisions of this Warrant with respect to compliance with the Act
     and with the limitations on assignments and transfers contained in this
     Section 7, the Company at its expense shall promptly issue to or on the
     ---------
     order of the Holder a new warrant or warrants of like tenor, in the name of
     the Holder or as the Holder (on payment by the Holder of any applicable
     transfer taxes) may direct, for the number of shares issuable upon exercise
     hereof.

          (e)  Compliance with Securities Laws.
               -------------------------------

               (i)  The Holder of this Warrant, by acceptance hereof,
          acknowledges that this Warrant and the shares of Common Stock to be
          issued upon exercise hereof are being acquired solely for the Holder's
          own account and not as a nominee for any other party, and for
          investment, and that the Holder will not offer, sell or otherwise
          dispose of this Warrant or any shares of Common Stock to be issued
          upon exercise hereof except under circumstances that will not result
          in a violation of the Act or any state securities laws. Upon exercise
          of this Warrant, the Holder shall, if requested by the Company,
          confirm in writing, in a form satisfactory to the Company, that the
          shares of Common Stock so purchased are being acquired solely for the
          Holder's own account and not as a nominee for any other party, for
          investment, and not with a view toward distribution or resale.

                                       6
<PAGE>

               (ii) The shares of Common Stock issued upon exercise hereof shall
          be stamped or imprinted with a legend in substantially the following
          form (in addition to any legend required by state securities laws):

THE SECURITIES REPRESENTED HEREBY HAVE BEEN ACQUIRED FOR INVESTMENT AND HAVE NOT
BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR ANY APPLICABLE
STATE SECURITIES LAWS. SUCH SECURITIES AND ANY SECURITIES ISSUED HEREUNDER OR
THEREUNDER MAY NOT BE SOLD OR TRANSFERRED IN THE ABSENCE OF SUCH REGISTRATION OR
AN EXEMPTION THEREFROM UNDER SAID ACT AND APPLICABLE LAWS. COPIES OF THE WARRANT
AGREEMENT COVERING THESE SECURITIES AND RESTRICTING THEIR TRANSFER OR SALE MAY
BE OBTAINED AT NO COST BY WRITTEN REQUEST MADE BY THE HOLDER OF RECORD HEREOF TO
THE SECRETARY OF THE COMPANY AT THE PRINCIPAL EXECUTIVE OFFICES OF THE COMPANY.

     8.   Reservation of Stock.  The Company covenants that during the term this
          --------------------
Warrant is exercisable, the Company will reserve from its authorized and
unissued Common Stock a sufficient number of shares to provide for the issuance
of Common Stock upon the exercise of this Warrant and, from time to time, will
take all steps necessary to amend its Certificate of Incorporation to provide
sufficient reserves of shares of Common Stock issuable upon exercise of the
Warrant. The Company further represents and covenants that all shares that may
be issued upon the exercise of this Warrant, all as set forth herein, will be
duly and validly authorized, fully paid and nonassessable and free from all
taxes, liens and charges in respect of the issue thereof (other than taxes in
respect of any transfer occurring contemporaneously or otherwise specified
herein). The Company agrees that its issuance of this Warrant shall constitute
full authority to its officers who are charged with the duty of executing stock
certificates to execute and issue the necessary certificates for shares of
Common Stock upon the exercise of this Warrant. The capitalization of the
Company is as set forth on Schedule A hereto.

     9.   Notices.
          -------

          (a)  Whenever the Exercise Price or number of shares purchasable
     hereunder shall be adjusted pursuant to Section 11 hereof, the Company
                                             ----------
     shall issue a certificate signed by its Chief Financial Officer setting
     forth, in

                                       7
<PAGE>

     reasonable detail, the event requiring the adjustment, the amount of the
     adjustment, the method by which such adjustment was calculated, and the
     Exercise Price and number of shares purchasable hereunder after giving
     effect to such adjustment, and shall cause a copy of such certificate to be
     mailed (by first-class mail, postage prepaid) to the Holder of this
     Warrant.

          (b)  In case:

               (i)   the Company shall take a record of the holders of its
          Common Stock (or other stock or securities at the time receivable upon
          the exercise of this Warrant) for the purpose of entitling them to
          receive any dividend or other distribution, or any right to subscribe
          for or purchase any shares of stock of any class or any other
          securities, or to receive any other right, or

               (ii)  of any capital reorganization of the Company, any
          reclassification of the capital stock of the Company, any
          consolidation or merger of the Company with or into another
          corporation, or any conveyance of all or substantially all of the
          assets of the Company to another corporation, or

              (iii)  of any voluntary dissolution, liquidation or winding-up of
          the Company,

          then, and in each case, the Company will mail or cause to be mailed to
          the Holder or Holders a notice specifying, as the case may be, (A) the
          date on which a record is to be taken for the purpose of such
          dividend, distribution or right, and stating the amount and character
          of such dividend, distribution or right, or (B) the date on which such
          reorganization, reclassification, consolidation, merger, conveyance,
          dissolution, liquidation or winding-up is to take place, and the time,
          if any is to be fixed, as of which the holders of record of Common
          Stock (or such stock or securities at the time receivable upon the
          exercise of this Warrant) shall be entitled to exchange their shares
          of Common Stock (or such other stock or securities) for securities or
          other property deliverable upon such reorganization, reclassification,
          consolidation, merger, conveyance, dissolution, liquidation or
          winding-up. Such notice shall be mailed at least 15 days prior to the
          date therein specified.

                                       8
<PAGE>

          (c)  All such notices, advices and communications shall be deemed to
     have been received (i) in the case of personal delivery, on the date of
     such delivery and (ii) in the case of mailing, on the third business day
     following the date of such mailing.

     10.  Amendments.
          ----------

          (a)  Any term of this Warrant may be amended or waived with the
     written consent of the Company and the Holders of Warrants representing not
     less than fifty-one percent (51%) of the shares of Common Stock issuable
     upon exercise of any and all outstanding Warrants.

          (b)  No waivers of, or exceptions to, any term, condition or provision
     of this Warrant, in any one or more instances, shall be deemed to be, or
     construed as, a further or continuing waiver of any such term, condition or
     provision.

     11.  Adjustments.  The Exercise Price and the number of shares purchasable
          -----------
hereunder are subject to adjustment from time to time as follows:

          (a)  Merger, Sale of Assets, etc.  If at any time while this Warrant,
               ---------------------------
     or any portion hereof, is outstanding and unexpired there shall be:

               (i)   a reorganization (other than a combination,
          reclassification, exchange or subdivision of shares otherwise provided
          for herein),

               (ii)  a merger or consolidation of the Company with or into
          another corporation in which the Company is not the surviving entity,
          or a reverse triangular merger in which the Company is the surviving
          entity but the shares of the Company's capital stock outstanding
          immediately prior to the merger are converted by virtue of the merger
          into other property, whether in the form of securities, cash, or
          otherwise, or

               (iii) a sale or transfer of the Company's properties and assets
          as, or substantially as, an entirety to any other person,

                                       9
<PAGE>

          then, as a part of such reorganization, merger, consolidation, sale or
          transfer, lawful provision shall be made so that the holder of this
          Warrant shall thereafter be entitled to receive upon exercise of this
          Warrant, during the period specified herein and upon payment of the
          Exercise Price then in effect, the number of shares of stock or other
          securities or property of the successor entity resulting from such
          reorganization, merger, consolidation, sale or transfer that a holder
          of the shares deliverable upon exercise of this Warrant would have
          been entitled to receive in such reorganization, consolidation,
          merger, sale or transfer if this Warrant had been exercised
          immediately before such reorganization, merger, consolidation, sale or
          transfer, all subject to further adjustment as provided in this
          Section 11. The foregoing provisions of this Section 11(a) shall
          ----------                                   -------------
          similarly apply to successive reorganizations, consolidations,
          mergers, sales and transfers and to the stock or securities of any
          other entity that are at the time receivable upon the exercise of this
          Warrant. If the per-share consideration payable to the holder hereof
          for shares or other securities in connection with any such transaction
          is in a form other than cash or marketable securities, then the value
          of such consideration shall be determined in good faith by the
          Company's Board of Directors. In all events, appropriate adjustment
          (as determined in good faith by the Company's Board of Directors)
          shall be made in the application of the provisions of this Warrant
          with respect to the rights and interests of the Holder after the
          transaction, to the end that the provisions of this Warrant shall be
          applicable after that event, as near as reasonably may be, in relation
          to any shares or other property deliverable after that event upon
          exercise of this Warrant.

          (b)  Reclassification, etc.  If the Company, at any time while this
               ---------------------
     Warrant, or any portion hereof, remains outstanding and unexpired by
     reclassification of securities or otherwise, shall change any of the
     securities as to which purchase rights under this Warrant exist into the
     same or a different number of securities of any other class or classes,
     this Warrant shall thereafter represent the right to acquire such number
     and kind of securities as would have been issuable as the result of such
     change with respect to the securities as would have been issuable as the
     result of such change with respect to the securities that were subject to
     the purchase rights under this Warrant immediately prior to such
     reclassification or other change and the Exercise Price

                                       10
<PAGE>

     therefor shall be appropriately adjusted, all subject to further adjustment
     as provided in this Section 11.
                         ----------

          (c)  Split, Subdivision or Combination of Shares.  If the Company at
               -------------------------------------------
     any time while this Warrant, or any portion hereof remains outstanding and
     unexpired shall split, subdivide or combine the securities as to which
     purchase rights under this Warrant exist, into a different number of
     securities of the same class, the Exercise Price for such securities shall
     be proportionately decreased in the case of a split or subdivision or
     proportionately increased in the case of a combination.

          (d) Adjustments for Dividends in Stock or Other Securities or
              ---------------------------------------------------------
     Property. If while this Warrant, or any portion hereof, remains outstanding
     --------
     and unexpired, the holders of the securities as to which purchase rights
     under this Warrant exist at the time shall have received, or, on or after
     the record date fixed for the determination of eligible stockholders, shall
     have become entitled to receive, without payment therefor, other or
     additional stock or other securities or property (other than cash) of the
     Company by way of dividend, then in each case, this Warrant shall represent
     the right to acquire, in addition to the number of shares of the security
     receivable upon exercise of this Warrant, and without payment of any
     additional consideration therefor, the amount of such other or additional
     stock or other securities or property (other than cash) of the Company that
     such holder would hold on the date of such exercise had it been the holder
     of record of the security receivable upon exercise of this Warrant on the
     date hereof and had thereafter, during the period from the date hereof to
     and including the date of such exercise, retained such shares and/or all
     other additional stock available by it as aforesaid during such period,
     giving effect to all adjustments called for during such period by the
     provisions of this Section 11.
                        ----------

          (e)  Certificate as to Adjustments.  Upon the occurrence of each
               -----------------------------
     adjustment or readjustment pursuant to this Section 11, the Company at its
                                                 ----------
     expense shall promptly compute such adjustment or readjustment in
     accordance with the terms hereof and furnish to each Holder of this Warrant
     a certificate setting forth such adjustment or readjustment and showing in
     detail the facts upon which such adjustment or readjustment is based.  The
     Company shall, upon the written request, at any time, of any such Holder,
     furnish or cause to be furnished to such Holder a like certificate setting
     forth:

                                       11
<PAGE>

               (i)   such adjustments and readjustments;

               (ii)  the Exercise Price at the time in effect; and

               (iii) the number of shares and the amount, if any, of other
          property that at the time would be received upon the exercise of the
          Warrant.

          (f)  No Impairment.  The Company will not, by any voluntary action,
               -------------
     avoid or seek to avoid the observance or performance of any of the terms to
     be observed or performed hereunder by the Company, but will at all times in
     good faith assist in the carrying out of all the provisions of this Section
                                                                         -------
     11 and in the taking of all such action as may be necessary or appropriate
     --
     in order to protect the rights of the Holder of this Warrant against
     impairment.

     12.  "Market Stand-Off" Agreement.  Each Holder hereby agrees that, during
           ----------------------------
the period of duration (up to, but not excluding, 180 days) specified by the
Company and an underwriter of Common Stock or other securities of the Company,
following the effective date of a registration statement of the Company filed
under the Act, it shall not, to the extent requested by the Company and such
underwriter, directly or indirectly sell, offer to sell, contract to sell
(including, without limitation, any short sale), grant any option to purchase or
otherwise transfer or dispose of (other than to donees who agree to be similarly
bound) any securities of the Company held by it at any time during such period,
except to the extent such securities are included in such registered offering
which may be promulgated in the future, or a registration relating solely to an
SEC Rule 145 transaction on Form S-4 or similar forms which may be promulgated
in the future.

     13.  Miscellaneous.
          -------------

          (a)  Governing Law.  THIS WARRANT AND ALL ACTS AND TRANSACTIONS
               -------------
     PURSUANT HERETO AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES HERETO SHALL
     BE GOVERNED, CONSTRUED AND INTERPRETED IN ACCORDANCE WITH THE LAWS OF THE
     STATE OF CALIFORNIA, WITHOUT GIVING EFFECT TO PRINCIPLES OF CONFLICTS OF
     LAW.

          (b)  Attorney's Fees.  If any action at law or in equity (including
               --------------
     arbitration) is necessary to enforce or interpret the terms of this
     Warrant, the

                                       12
<PAGE>

     prevailing party shall be entitled to reasonable attorney's fees, costs and
     necessary disbursements in addition to any other relief to which such party
     may be entitled.

IN WITNESS WHEREOF, PETsMART.com, Inc. has caused this Warrant to be executed by
its officers hereunto duly authorized.

Dated:  October 19, 1999

HOLDER:  Big Dog USA, Inc.          PETsMART.COM, INC.

   /s/  Andrew Feshback                 /s/ Tom McGovern
---------------------------         --------------------------------
By:  Andrew Feshback                By:  Tom McGovern
   ------------------------            -----------------------------
Title:  CEO                         Title:  Chief Executive Officer
      ---------------------               --------------------------

                                       13
<PAGE>

                             NOTICE OF EXERCISE

To:  PETsMART.com, Inc.

     The undersigned hereby irrevocably, subject to the terms and conditions
contained in the attached Warrant, (A) elects to purchase _____ shares of Common
Stock of PETsMART.com, Inc., pursuant to the provisions of Section 3(a) of the
                                                           ------------
attached Warrant, and tenders herewith payment of the purchase price for such
shares in full, or (B) as required by the Company, elects to exercise this
Warrant for the purchase of _____ shares of Common Stock, pursuant to the
provisions of Section 3(c) of the attached Warrant.
              ------------

     (2) In exercising this Warrant, the undersigned hereby confirms and
acknowledges that the shares of Common Stock are being acquired solely for the
account of the undersigned and the undersigned will not offer, sell or otherwise
dispose of any such shares of Common Stock except under circumstances that will
not result in a violation of the Securities Act of 1933, as amended, or any
applicable state securities laws.

     (3) Please issue a certificate or certificates representing said shares of
Common Stock in the name of the undersigned or in such other name as is
specified below.

                                           _________________________________
                                           (Name)

                                           _________________________________
                                           (Name)

     (4) Please issue a new Warrant for the unexercised portion of the attached
Warrant in the name of the undersigned or in such other name as is specified
below:

                                            ________________________________
                                            (Name)

_____________________________               ________________________________
(Date)                                      (Name)

                                       14
<PAGE>

                                ASSIGNMENT FORM

     FOR VALUE RECEIVED, the undersigned registered owner of this Warrant hereby
sells, assigns and transfers unto the Assignee named below the attached Warrant,
together with all of the rights of the undersigned under the Warrant, with
respect to the number of shares of Common Stock set forth below:

 Name of Assignee                  Address                   No. of Shares

and does hereby irrevocably constitute and appoint ____________ Attorney to make
such transfer on the books of PETsMART.com, Inc., maintained for the purpose,
with full power of substitution in the premises.

     The undersigned also represents that, by assignment hereof, the Assignee
acknowledges that this Warrant and the securities to be issued upon exercise
hereof are being acquired for investment and that the Assignee will not offer,
sell or otherwise dispose of this Warrant or any securities to be issued upon
exercise hereof except (i) under circumstances which will not result in
violation of the Securities Act of 1933, as amended, or any state securities
laws and (ii) in accordance with the terms of the Warrant. Further, the Assignee
has acknowledged that upon exercise of this Warrant, the Assignee shall, if
requested by the Company, confirm in writing, in a form satisfactory to the
Company, that the securities so purchased are being acquired for investment and
not with a view toward distribution or resale.

Dated:_____________________

                                             ________________________________
                                             Signature of Holder
                                             Note: The above signature should
                                             correspond exactly with the name on
                                             the face of the attached Warrant.

                                       15

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00001-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00001-of-00352.parquet"}]]