<PAGE>

                                                                     EXHIBIT 4.3

          THE SECURITIES EVIDENCED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED
          UNDER THE SECURITIES ACT OF 1933 (THE "ACT") AND MAY NOT BE OFFERED,
          SOLD OR OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED UNLESS AND
          UNTIL REGISTERED UNDER THE ACT OR, IN THE OPINION OF COUNSEL IN FORM
          AND SUBSTANCE SATISFACTORY TO THE COMPANY, SUCH OFFER, SALE OR
          TRANSFER, PLEDGE OR HYPOTHECATION IS IN COMPLIANCE THEREWITH.



                       SERIES E PREFERRED STOCK WARRANT

                                      of

                          TERRAPIN TECHNOLOGIES, INC.



          THIS CERTIFIES THAT STEVEN M. COSTELLA, TRUSTEE, OR THE SUCCESSOR
     TRUSTEE, UNDER THE STEVEN M. COSTELLA TRUST, DATED MAY 8, 1989
     ("Warrantholder") is entitled to subscribe for and purchase from TERRAPIN
     TECHNOLOGIES, INC., a Delaware corporation (the "Company") 22 fully-paid
     and non-assessable shares of the Company's Series E Preferred Stock (the
     "Preferred), at a price of $50.00 per share (the "Warrant Price"), such
     price and such number of shares being subject to adjustment upon the
     occurrence of the contingencies set forth in this Warrant. As of the date
     hereof, each share of Series E Preferred is convertible into 66-2/3 shares
     of Common stock. This Warrant is granted in connection with the extension
     of a loan against certain equipment pursuant to that certain Master Loan
     Agreement by and between the Company and Venture Leasing Associates dated
     December 31, 1992.

          Upon delivery of this Warrant, together with payment of the Warrant
     Price of the shares of the Preferred thereby purchased, at the principal
     office of the Company or at such other office or agency as the Company may
     designate by notice in writing to the holder hereof, the holder of this
     Warrant shall be entitled to receive a certificate or certificates for the
     shares of Preferred so purchased. The date at which the Company receives
     (i) the Warrant and (ii) payment for the shares of Preferred, either by
     payment in cash or by check, or by notice of the Warrantholder's intent to
     use the proceeds from the sale of shares at a Public Offering (as defined
     below), if any, or notice of intent to use shares of Preferred as payment,
     both as described in Section 1 below, or such later date as such notice
     shall specify, shall be referred to herein as the "Exercise Date." All
     shares of Preferred which may be issued upon the exercise of this Warrant
     will, upon issuance, be fully paid and non-assessable and free from all
     taxes, liens and charges with respect to the issue thereof.

          This Warrant is subject to the following terms and conditions:

          1.   Exercise of Warrant: This Warrant may be exercised in whole or in
               -------------------
     part, at any time on or before the earlier of (i) December 31, 2002, (ii)
     consolidation or merger of the Company in which the shareholders of the
     Company do not own a majority of the combined voting power of the surviving
     corporation or its parent after such consolidation or merger, and (iii) the
     closing of an underwritten public offering (a "Public Offering") of the
     Company's equity securities pursuant
<PAGE>

     to a registration statement under the Securities Act of 1933, as amended
     (the "Act"), by the surrender of this Warrant at the principal office of
     the Company and by the payment to the Company, in the manner provided for
     in the following paragraph, of the Warrant Price for all of the Preferred
     purchased. The Company shall, within 20 days after such delivery, prepare a
     certificate for the shares of Preferred purchased in the name of the holder
     of this Warrant, or as such holder may direct (subject to the restrictions
     upon transfer contained herein and upon payment by such holder hereof of
     any applicable transfer taxes).

          This Warrant may be exercised by the payment to the Company, by cash
     or check, or from the proceeds of the sale of shares of Common Stock issued
     upon conversion of shares of Preferred issued upon exercise of this Warrant
     sold by the Warrantholder pursuant to a Public Offering of an amount equal
     to the aggregate Warrant Price of the shares being purchased, if the
     Warrantholder shall so participate in a Public Offering. The rights of the
     Warrantholder, to so participate, shall be governed by the Registration
     Rights Agreement (as hereinafter defined) and not this Warrant. In lieu of
     exercising this Warrant as described above, the Warrantholder may elect to
     receive shares equal to the value (as determined below) of this Warrant (or
     the portion thereof being cancelled,' by surrender of this Warrant at the
     principal office of the Company together with notice of such election
     (which notice shall include the number of shares being exercised
     hereunder), in which event the Company shall issue to the Warrantholder a
     number of shares of Preferred equal to the quotient obtained by dividing
     (x) the value of the shares of Preferred being exercised (the "Exercised
     Shares") on the Exercise Date, which value shall be determined by
     subtracting (A) the aggregate Warrant Price of the Exercised Shares
     immediately prior to the exercise of the Warrant from (B) the aggregate
     fair market value of the Exercised Shares on the Exercise Date by (y) the
     fair market value of one share of Preferred (or Common Stock if the
     Preferred has been converted into Common Stock) as of the Exercise Date. No
     fractional shares shall be issuable upon exercise of this Warrant, and if
     the number of shares to be issued determined in accordance with the
     foregoing formula is other than a whole number, the Company shall pay to
     the Warrantholder an amount in cash equal to the fair market value of the
     resulting fractional share on the Exercise Date.

          The exercise of this Warrant may be made contingent upon (i) the
     closing of a Public Offering, (ii) the closing of any consolidation or
     merger which would trigger termination of the Warrant under clause (ii) of
     the first paragraph of this section 1, or (iii) the sale of all or
     substantially all of the assets of the Company. The Company shall notify
     the holder if an event or transaction of the kind described in this section
     is proposed at least fifteen days prior to the closing of such event or
     transaction; such notice shall also contain such details of the proposed
     event or transaction as are reasonable in the circumstances and notice that
     this Warrant shall expire upon the closing thereof. The information
     contained in such notice shall be kept confidential by the Warrantholder
     until a public announcement of such information has occurred.

          Certificates for the shares issuable upon exercise of this Warrant
     and, if applicable, a new warrant evidencing the balance of the shares
     remaining subject to this Warrant shall be issued as of the Exercise Date
     and shall be delivered to the holder within thirty days following the
     Exercise Date.

          For purposes of this Section 1, the fair market value of the Preferred
shall be determined as follows:

          (i)    If this Warrant is exercised in connection with and contingent
upon a Public Offering, and if the Company's registration statement relating to
such Public Offering has been declared effective by the Securities and Exchange
Commission, then the fair market value shall be the initial "Price to Public"
specified in the final prospectus with respect to such offering.
<PAGE>

          (ii)   If this Warrant is not exercised in connection with and
contingent upon a Public Offering, then the fair market value shall be
determined in good faith by the Company's Board of Directors.

     2.   Transfer of Warrant.  Except in accordance with the conditions
          -------------------
contained in Section 3 hereof, this Warrant and all rights hereunder are not
transferable.

     3.   Condition of Transfer or Exercise of Warrant. It shall be a condition
          --------------------------------------------
contained any transfer or exercise of this Warrant that the Company shall have
received, at the time of such transfer or exercise, a representation in writing
that this Warrant (or portion hereof transferred) or the shares of Preferred
being issued upon such exercise, as the case may be, are being acquired for
investment not with a view to any sale or distribution thereof, or a statement
of the pertinent facts covering any proposed distribution thereof. It shall be a
further condition to any transfer of this Warrant or of any or all of the shares
of Preferred issued upon exercise of this Warrant, or Common Stock issued upon
conversion of the Preferred, other than a transfer registered under the Act,
that the Company shall have received a legal opinion, in form and substance
satisfactory to the Company and its counsel, reciting the pertinent
circumstances surrounding the proposed transfer and stating that such transfer
is exempt from the prospectus and the registration requirements of the Act. The
requirement of a legal opinion shall not apply to the transfer of this Warrant
or any part thereof to a partnership of which the Warrantholder is a partner or
to the beneficial owners of such partnership without further consideration, so
long as such transfer is in compliance with applicable securities laws. Each
certificate evidencing the shares of Preferred issued upon exercise of this
Warrant, or Common Stock issued upon conversion of the Preferred, or upon any
transfer of such shares (other than a transfer registered under the Act or any
subsequent transfer or shares so registered) shall, at the option of the
Company, contain a legend, in form and substance satisfactory to the Company and
its counsel, restricting the transfer of such shares to sales or other
dispositions exempt from the requirements of the Act.

          It shall be a further condition to each such transfer that the
transferee shall receive and accept a Warrant, of like tenor and date, executed
by the Company.

     4.   Adjustment of Warrant Price and Number of Shares Purchasable
          ------------------------------------------------------------
Hereunder.  The Warrant Price and the number of shares purchasable hereunder
---------
shall be subject to adjustment from time to time in accordance with the
following provisions, provided, however, that no such adjustment shall be made
if a corresponding adjustment is made to the "Conversion Price" of the Preferred
in the Company's Certificate of Incorporation, as amended:

          (a) Subdivisions.  In case the Company shall at any time subdivide the
              ------------
outstanding shares of its Preferred Stock, the Warrant Price in effect
immediately prior to such subdivision shall be proportionately decreased, and in
case the Company shall at any time combine the outstanding shares of its
Preferred Stock, the Warrant Price in effect immediately prior to such
combination shall be proportionately increased, effective at the close of
business on the date of such subdivision or combination, as the case may be.

          (b) Stock Dividends.  In case the Company shall at any time pay a
              ---------------
dividend with respect to Preferred payable in Preferred, then the Warrant Price
in effect immediately prior to the record date for distribution of such dividend
shall be adjusted to that price determined by multiplying the Warrant Price in
effect immediately prior to such record date by a fraction (i) the numerator of
which shall be the total number of shares of Preferred outstanding immediately
prior to such dividend and (ii) the denominator of which shall be the total
number of shares of Preferred outstanding immediately after such dividend.

          (c) Number of Shares. Upon each adjustment pursuant to subdivisions
              ----------------
(a) or (b) of this Section 4, the registered holder of this Warrant shall
thereafter (until another such adjustment) be entitled to purchase, at the
adjusted Warrant Price, the number of shares of Preferred, calculated to the
nearest full share, obtained by multiplying the number of shares of Preferred
purchasable hereunder immediately prior to such adjustment by the Warrant Price
in effect prior to such adjustment and dividing the product so obtained by the
adjusted Warrant price.

                                       5
<PAGE>

          (d) Reclassification or Merger.  In case of any reclassification,
              --------------------------
change or conversion of securities of the class or series issuable upon exercise
of this Warrant (other than as a result of a subdivision or combination
described above), the Company, or such successor or purchasing corporation, as
the case may be, shall duly execute and deliver to the Warrantholder a new
warrant so that the Warrantholder shall have the right to receive, at a total
purchase price not to exceed that payable upon the exercise of the unexercised
portion of this Warrant, and in lieu of the shares of Preferred theretofore
issuable upon exercise of this Warrant, the kind and amount of shares of stock,
other securities, money and property receivable upon such reclassification,
change or merger by a holder of the number of shares of Preferred then
purchasable under this Warrant. Such new warrant shall provide for adjustments
that shall be as nearly equivalent as may be practicable to the adjustments
provided for in this Section 4. The provisions of this subparagraph (d) shall
similarly apply to successive reclassifications, changes, and mergers.

          (e) Antidilution Rights.  The other antidilution rights applicable to
              -------------------
the Preferred and the Common Stock of the Company are set forth in the
Certificate of Incorporation (the "Certificate"), as amended from time to time,
a true and complete copy in its current form which is attached hereto as Exhibit
A. The Company shall promptly provide the Warrantholder hereof with any
restatement, amendment or modification to the Certificate promptly after the
same has been made.

     5.   Notices.
          -------

          (a) Upon any adjustment of the Warrant Price and any increase or
decrease in the number of shares of Preferred purchasable upon the exercise of
this Warrant, then, and in each such case, the Company, within thirty (30) days
thereafter, shall give written notice thereof to the registered holder of this
Warrant at the address of such holder as shown on the books of the Company which
notice shall state the Warrant Price as adjusted and the increased or decreased
number of shares purchasable upon the exercise of this Warrant, setting forth in
reasonable detail the method of calculation of each.

          (b) In the event that the Company shall propose at any time to effect
a public offering of the Company's Common Stock pursuant to an effective
registration statement under the Act, the Company shall send to the
Warrantholder at least twenty days' prior written notice of the date when the
same is anticipated to take place; provided, however, that the failure to give
such notice shall not give the Warrantholder the right to delay or otherwise
restrain or affect the Public Offering. Such written notice shall be given by
first class mail, postage prepaid, addressed to the Warrantholder at the address
as shown on the books of the Company for the Warrantholder.

     6.   Registration. The Warrantholder shall be a "Holder" and the shares of
          ------------
Common Stock issuable upon conversion of the Preferred issuable upon exercise of
this Warrant shall be "Registrable Securities" under that certain Investor
Rights Agreement by and among the Company and the other parties thereto dated as
of December 3, 1992 (the "Registration Rights Agreement"). Waiver, termination,
and amendment of the Registration Rights Agreement shall be controlled by the
provisions thereof, without regard to this Warrant.

     7.   Representations of Warrantholder.  Concurrently with the receipt of
          --------------------------------
this Warrant, the Warrantholder shall have executed the Investment
Representation Statement in the form attached hereto as Exhibit B.

     8.   Representations and Warranties of the Company.
          ---------------------------------------------

          The Company represents and warrants to the Warrantholder as follows:

          (a) This Warrant has been duly authorized and executed by the Company
and is a valid and binding obligation of the Company, enforceable in accordance
with its terms except as to (i) the effect of applicable bankruptcy and similar
laws affecting the rights of creditors, and (ii) the effect of rules of law

                                       5
<PAGE>

governing specific performance, injunctive relief and other equitable remedies.

          (b) The Preferred has been duly authorized and reserved for issuance
by the Company and, when issued in accordance with the terms hereof, will be
validly issued, fully paid and non-assessable, and free from all taxes, liens
and changes with respect to the issues of such shares.

          (c) The rights, preference, privileges and restrictions granted to or
imposed upon the Preferred and the holders thereof are as set forth in the
Company's Certificate of as Incorporation, amended, a true and complete copy of
which has been delivered to the Warrantholder.

          (d) The execution and delivery of this Warrant is not, and the
issuance of the Preferred upon exercise of this Warrant in accordance with the
terms hereof is not inconsistent with the Company's Certificate of Incorporation
or Bylaws, does not contravene any law, governmental rule or regulation,
judgment or order applicable to the Company, and does not conflict with or
contravene any provision of, or constitute a default under, any indenture,
mortgage, contract or other instrument of which the Company is a party or by
which it is bound or require the consent or approval of, the giving of notice
to, the registration or filing with or the taking of any action in respect of or
by, any federal, state or local government authority or agency or other person,
other than state or federal securities law filings.

          (e) During the period within which this Warrant may be exercised, the
Company will at all times have authorized and reserved for the purpose of the
issue upon exercise of this Warrant a sufficient number of shares of its
Preferred to provide for the exercise of this Warrant and a sufficient number of
shares of its Common Stock to provide for the conversion of the Preferred into
Common Stock.

     9.   Miscellaneous.
          -------------

          (a) The terms of this Warrant shall be binding upon and shall inure to
the benefit of any successors or assigns of the Company and of the holder or
holders hereof and of the Preferred issued or issuable upon the exercise hereof,
and all of the obligations of the Company relating to the Preferred issuable
upon exercise of this Warrant shall survive the exercise of this Warrant.

          (b) No holder of this Warrant, as such, shall be entitled to vote or
receive dividends or be deemed to be a shareholder of the Company for any
purpose, nor shall anything contained in this Warrant be construed to confer
upon the holder of this Warrant, as such, any rights of a shareholder of the
Company or any right to vote, give or withhold consent to any corporate action,
receive notice of meetings, receive dividends or subscription rights, or
otherwise.

          (c) Receipt of this Warrant by the holder hereof shall constitute
acceptance of and agreement to the foregoing terms and conditions.

          (d) The Company will not, by amendment of its Certificate of
Incorporation or through any other means, avoid or seek to avoid the observance
or performance of any of the terms of this Warrant, but will at all times in
good faith assist in the carrying out of all such terms 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.

          (e) Upon receipt of evidence reasonably satisfactory to the Company of
the loss, theft, destruction or mutilation of this Warrant and, in the case of
any such loss, theft or destruction, upon delivery of an indemnity agreement
reasonably satisfactory in form and amount to the Company, or in the case of any
such mutilation, upon surrender and cancellation of such Warrant, the Company
will execute and deliver, in lieu thereof, a new Warrant of like date and tenor.

                                       5
<PAGE>

          (f) This Warrant shall be governed by, construed and enforced in
accordance with the laws of the State of California, as applied to agreements
made and performed in California by residents of the State of California.

          (g) So long as this Warrant has not terminated, the Warrantholder
shall be entitled to receive unaudited quarterly and audited annual financial
statements.

     IN WITNESS WHEREOF, the Company has caused this Warrant to be signed by its
duly authorized officer.



Signature: /s/ Reinaldo Gomez                     Dated: 12/22/97
           TERRAPIN TECHNOLOGIES, INC.


Accepted: WARRANTHOLDER


Signature: /s/ Steven M. Costella, Trustee