<Page>


                                                                    Exhibit 4.10

                                    DEBENTURE

THIS DEBENTURE AND ANY SHARES ISSUABLE UPON THE EXERCISE OF THIS DEBENTURE HAVE
NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 (THE "ACT"), NOR UNDER ANY
STATE SECURITIES LAW AND SUCH SECURITIES MAY NOT BE PLEDGED, SOLD, ASSIGNED,
HYPOTHECATED, OR OTHERWISE TRANSFERRED EXCEPT AS PERMITTED BY THE PROVISIONS OF
REGULATION S UNDER THE ACT OR PURSUANT TO REGISTRATION UNDER THE ACT OR AN
AVAILABLE EXEMPTION FROM REGISTRATION. HEDGING TRANSACTIONS INVOLVING THESE
SECURITIES MAY NOT BE CONDUCTED UNLESS IN COMPLIANCE WITH THE ACT.

THE TRANSFER OF THIS DEBENTURE AND THE SHARES ISSUABLE UPON THE EXERCISE HEREOF
ARE RESTRICTED AS DESCRIBED HEREIN.

THE SALE, ASSIGNMENT, TRANSFER, PLEDGE AND OTHER DISPOSITION OF THIS DEBENTURE
AND THE SHARES ISSUABLE UPON THE EXERCISE OF THIS DEBENTURE ARE RESTRICTED BY
THE INVESTOR'S RIGHTS AGREEMENT (THE "INVESTOR'S RIGHTS AGREEMENT"), DATED
JANUARY 23, 2001. A COPY OF THE INVESTOR'S RIGHTS AGREEMENT IS ON FILE WITH THE
CORPORATE SECRETARY AT THE PRINCIPAL EXECUTIVE OFFICES OF THE COMPANY. A COPY
THEREOF MAY BE OBTAINED AT NO COST UPON WRITTEN REQUEST THEREFOR MADE BY THE
HOLDER OF RECORD OF THIS CERTIFICATE TO THE CORPORATE SECRETARY AT THE PRINCIPAL
OFFICES OF THE COMPANY.

No.      ____                                             U.S. $_________

                                  ON2.COM INC.

              SERIES A CONVERTIBLE DEBENTURE DUE JANUARY ___, 2005

        THIS DEBENTURE is one of a duly authorized issue of up to $2,000,000 in
Debentures of ON2.COM INC., a corporation organized and existing under the laws
of the State of Delaware (the "Company") designated as its Series A Convertible
Debentures due 2005.

        The Company has issued this Debenture pursuant to a Unit Subscription
Agreement, dated as of January 23, 2001 (the "Unit Subscription Agreement"),
together with a related warrant (the "Warrant"), and has granted certain
registration rights pursuant to the terms of an Investor's Rights Agreement,
dated as of January 23, 2001 (the "Investor's Rights Agreement"). Pursuant to
the Unit Subscription Agreement, the Company may issue additional Debentures to
the Holder


<Page>

with substantially the same terms as this Debenture (together with this
Debenture, the "Debentures"). The date on which this Debenture is issued is
referred to herein as the "Issue Date".

         FOR VALUE RECEIVED, the Company promises to pay to ABANAT LIMITED, a
corporation organized and existing under the laws of _____________, the
registered holder hereof (the "Holder"), the principal sum of ____________ and
00/100 Dollars (US $_______.00) on January ___, 2005 (the "Maturity Date").
Interest shall not accrue on this Debenture, and only the principal sum shall be
payable and provided for by the Company on the Maturity Date or upon any
redemption or prepayment of this Debenture.

         This Debenture is subject to the following additional provisions:

         1. EXCHANGE. The Debentures are issuable in denominations of Ten
Thousand Dollars (US$10,000.00) and integral multiples thereof (unless at the
time of issue of the Debenture, the aggregate amount due to the Company under
the Unit Subscription Agreement is not an integral multiple of $10,000.00, in
which case the Debentures may be issued in other denominations). The Debentures
are exchangeable for an equal aggregate principal amount of Debentures of
different authorized denominations, as requested by the Holder surrendering the
same, and shall bear the same date as the Debenture for which it is exchanged.
No service charge will be made for such registration or transfer or exchange.

         2. RESTRICTIONS ON TRANSFER. This Debenture has been issued subject to
investment representations of the original purchaser hereof and may be
transferred or exchanged only in compliance with Regulation S ("Regulation S")
of the Securities Act of 1933, as amended (the "Act"), or pursuant to
registration under the Act or an available exemption from registration and in
compliance with other applicable state and foreign securities laws and the
Investor's Rights Agreement. The Company covenants and agrees that it will not
register any transfer of this Debenture which is not made in accordance with the
provisions of Regulation S, pursuant to registration under the Act or pursuant
to an available exemption from registration. In the event of any proposed
transfer of this Debenture, the Company may require, prior to issuance of a new
Debenture in the name of such other person, that it receive reasonable transfer
documentation including legal opinions, satisfactory to the Company, that the
issuance of the Debenture in such other name does not and will not violate the
provisions of Regulation S or cause a violation of the Act or any applicable
state or foreign securities laws. Prior to due presentment for transfer of this
Debenture, the Company and any agent of the Company may treat the person in
whose name this Debenture is duly registered on the Company's debenture register
as the owner hereof for the purpose of receiving payment as herein provided and
for all other purposes, whether or not this Debenture be overdue, and neither
the Company nor any such agent shall be affected by notice to the contrary.

         3. CONVERSION. The Holder is entitled, at its option after the date
that is 180 days after the date hereof, subject to the following provisions of
this Section 4, to convert all or a



                                       2
<Page>

portion of this Debenture into shares of Common Stock of the Company, $0.01 par
value per share ("Common Stock"), at any time until the Maturity Date, at a
conversion price for each share of Common Stock equal to the amount of $0.___
[the lower of $0.45 or the average closing price of the common stock for a
ten-day period] (the "Conversion Price"); PROVIDED that the principal amount
being converted is at least US $10,000.00 (unless if at the time of such
election to convert the aggregate principal amount of all Debentures registered
to the Holder is less than Ten Thousand Dollars (US $10,000.00), then the whole
amount thereof). The number of shares of Common Stock issuable upon exercise of
this Debenture (the "Conversion Shares") and the Conversion Price may be
adjusted from time to time as hereinafter set forth. The number of Conversion
Shares into which such Debentures are convertible shall be determined by
dividing (a) the principal amount of the Debentures to be converted by (b) the
Conversion Price then in effect.

         In order to convert the principal amount of this Debenture, or any
portion thereof, the Holder shall send by facsimile transmission (and confirm
such transmission by telephone or voicemail message), a notice of conversion to
the Company and to the Company's transfer agent, Corporate Stock Transfer,
located at 3200 Cherry Creek Drive South, Suite 430, Denver, Colorado 80209 or
any successor thereto, stating the principal amount to be converted and the
applicable Conversion Price, and prior to Conversion, the Holder must physically
surrender this Debenture to the Company.

         No fractional shares of Common Stock or scrip representing fractions of
shares will be issued on conversion, but the number of shares issuable shall be
rounded to the nearest whole share. The date on which notice of conversion is
given (the "Conversion Date") shall be deemed to be the date on which the Holder
faxes or otherwise delivers the conversion notice ("Notice of Conversion"),
substantially in the form annexed hereto as Exhibit A, duly executed, to the
Company, provided that the Holder shall deliver to the Company's transfer agent
or the Company the original Debentures being converted within five (5) business
days thereafter (and if not so delivered within such time, the Conversion Date
shall be the date on which the later of the Notice of Conversion and the
original Debentures being converted is received by the Company). Facsimile
delivery of the Notice of Conversion shall be accepted by the Company at
facsimile number (917) 237-1544; ATTN: Corporate Secretary, or at such other
facsimile number as the Company may provide to the Holder.

         4. REPAYMENT. Any Debentures not previously converted as of the
Maturity Date, shall be, unless otherwise designated by the Holder,
automatically converted, as of the Maturity Date at the applicable Conversion
Price. The Holder may elect, by notice to the Company at any time within ten
(10) days after the Maturity Date, that the Company repay any Debentures which
have not yet been converted as of the Maturity Date by payment of the principal
amount of the Debenture.



                                       3
<Page>

         5. ADJUSTMENTS TO CONVERSION PRICE. The number of Conversion Shares and
the Conversion Price shall be subject to adjustment from time to time as
provided in this Section. There shall be no adjustment hereunder with respect to
(A) the issuance or sale of shares or options to purchase shares of the Company
Common Stock to employees, officers, directors and consultants of the Company
and its subsidiaries (as such number of shares is appropriately adjusted for
subsequent stock splits, stock combinations, stock dividends and
recapitalizations) pursuant to plans or arrangements approved by the Company's
Board of Directors; (B) the issue or sale to other entities or the owners
thereof for acquisition purposes; (C) the issue and sale to banks, savings and
loan associations, equipment lessors or other similar lending institutions in
connection with such entities providing working capital credit facilities or
equipment financing to the Company; (D) the issuance of Common Stock to
Crossover Ventures, Inc. or its successors or assigns under the terms of the
equity line of credit arrangement, as such may be amended from time to time, and
(E) the issuance of Common Stock upon conversion of any shares of any series of
the Company's Preferred Stock, the Company's Series A Convertible Debentures due
2006 or the Warrants.

         5.1 If, at any time while any portion of this Debenture remains
outstanding, the Company shall pay or make a dividend or other distribution on
any class of capital stock of the Company in Common Stock, then, following the
record date for the determination of holders of Common Stock entitled to receive
such stock dividend or other distribution, the Conversion Price shall be
appropriately decreased so that the number of shares of Common Stock issuable on
exercise of this Debenture shall be increased in proportion to such increase in
outstanding shares.

         5.2 If, at any time while any portion of this Debenture remains
outstanding, (a) the outstanding shares of Common Stock shall be subdivided into
a greater number of shares of Common Stock, then, following the date upon which
such subdivision becomes effective, the Conversion Price shall be appropriately
decreased so that the number of shares of Common Stock issuable on exercise of
this Debenture shall be increased in proportion to such increase in outstanding
shares, and, (b) if outstanding shares of Common Stock shall each be combined
into a smaller number of shares of Common Stock, then, following the date upon
which such combination becomes effective, the Conversion Price shall be
appropriately increased so that the number of shares of Common Stock issuable on
exercise of this Debenture shall be decreased in proportion to such decrease in
outstanding shares.

         5.3 The reclassification of Common Stock into securities (other than
Common Stock) and/or cash and/or other consideration shall be deemed to involve
a subdivision or combination, as the case may be, of the number of shares of
Common Stock outstanding immediately prior to such reclassification into the
number or amount of securities and/or cash and/or other consideration
outstanding immediately thereafter, and the effective date of such
reclassification shall be deemed to be "the day upon which such subdivision
becomes effective" or "the day upon which such combination becomes effective,"
as the case may be, within the meaning of Section 5.1.



                                       4
<Page>

         5.4 If, at any time while any portion of this Debenture remains
outstanding, the Company issues or sells any Convertible Securities (as defined
below) or any shares of Common Stock for a consideration per share less than
Fair Market Value (as defined below) of the Common Stock determined on the date
of such issuance or sale, then immediately upon such issue or sale or deemed
issue or sale, the Conversion Price shall be reduced to the Conversion Price
determined by dividing (A) the sum of (i) the product derived by multiplying the
Conversion Price in effect immediately prior to such issue or sale by the number
of shares of Common Stock Deemed Outstanding (as defined below) immediately
prior to such issue or sale, plus (ii) the consideration, if any, received by
the Company upon such issue or sale, by (B) the number of shares of Common Stock
Deemed Outstanding immediately after such issue or sale. In such instances, the
number of Conversion Shares shall be increased by multiplying such number of
shares by a fraction, of which the numerator will be the Conversion Price in
effect immediately prior to such issue or sale, and the denominator will be the
Conversion Price immediately after such issue or sale. "Common Stock Deemed
Outstanding" means, at any given time, the number of shares of Common Stock
actually outstanding at such time, plus the number of shares of Common Stock
deemed to be outstanding assuming exercise and/or conversion of the Company's
Options (as defined below) and Convertible Securities, whether or not such
Options or Convertible Securities are actually exercisable at such time.
"Options" means any rights, warrants or options sold or granted by the Company
to subscribe for or purchase Common Stock or Convertible Securities.
"Convertible Securities" means any stock or securities directly or indirectly
convertible into or exchangeable for Common Stock. "Fair Market Value" means, as
of any date, the value of a share of Common Stock, determined as follows: (i) if
such Common Stock is then listed on a national securities exchange, its closing
price on the date of determination on the principal national securities exchange
on which the Common Stock is listed or admitted to trading, as reported in The
Wall Street Journal; (ii) if such Common Stock is then quoted on the Nasdaq
National Market, its closing price on the Nasdaq National Market on the date of
determination, as reported in The Wall Street Journal; (iii) if such Common
Stock is not quoted on the Nasdaq National Market nor listed or admitted to
trading on a national securities exchange, the average of the closing bid and
asked prices on the date of determination, as reported in The Wall Street
Journal; or (iv) if none of the foregoing is applicable, by the Board of
Directors of the Company acting in good faith.

         5.5 In the event of any capital reorganization of the Company, any
reclassification of the stock of the Company (other than a change in par value
or from par value to no par value or from no par value to par value or as a
result of a stock dividend or subdivision, split-up or combination of shares),
any sale or transfer to another Person of the property of the Company as an
entirety or substantially as an entirety, or any consolidation or merger of the
Company with or into another corporation (where the Company is not the surviving
corporation or where there is a change in or distribution with respect to the
Common Stock), this Debenture shall after such reorganization, reclassification,
consolidation, transfer or merger be exercisable for the kind and number of
shares of stock or other securities or property of the Company or of the
successor corporation resulting from such consolidation, transfer or surviving
such merger, if any, to which



                                       5
<Page>

the holder of the number of shares of Common Stock deliverable (immediately
prior to the time of such reorganization, reclassification, consolidation or
merger) upon exercise of this Debenture would have been entitled upon such
reorganization, reclassification, consolidation, transfer or merger. The
provisions of this clause shall similarly apply to successive reorganizations,
reclassifications, consolidations, transfers, or mergers.

         5.6 NOTICE OF ADJUSTMENT OF CONVERSION PRICE. Whenever the Conversion
Price is adjusted as herein provided:

            (i) the Company shall compute the adjusted Conversion Price in
accordance with this Section 5 and shall prepare a certificate signed by an
officer of the Company, setting forth the adjusted Conversion Price and showing
in reasonable detail the facts upon which such adjustment is based, and such
certificate shall forthwith be filed at each office or agency maintained for
this Debenture; and

            (ii) a notice stating that the Conversion Price has been adjusted
and setting forth the adjusted Conversion Price shall forthwith be prepared by
the Company, and as soon as practicable after it is prepared, such notice shall
be mailed by the Company at its expense to the Holder at its last address as it
shall appear in the debenture register.

         5.7 OTHER DILUTIVE EVENTS. If any event occurs as to which the
provisions of this Section 5 are not strictly applicable or, if strictly
applicable, would not fairly and adequately protect the conversion rights of the
Holder in accordance with the essential intent and principles of such
provisions, then the Board of Directors shall make such adjustments in the
application of such provisions, in accordance with such essential intent and
principles, as shall be reasonably necessary to protect such purchase rights as
aforesaid; provided that no such adjustment will increase the Conversion Price
or decrease the number of shares of Common Stock obtainable as otherwise
determined pursuant to this Section 5.

         6. REPRESENTATIONS OF HOLDER. The Holder of the Debenture, by
acceptance hereof, represents and warrants that it is not a U.S. person, as
defined by Regulation S, and is not purchasing the debenture for the account or
benefit of a U.S. person and agrees that this Debenture is being acquired for
investment and that such Holder will not offer, sell or otherwise dispose of
this Debenture or the Shares of Common Stock issuable upon conversion thereof
except in compliance with the provisions of Regulation S pursuant to
registration under the Act or pursuant to an available exemption from
registration and under circumstances which will not result in a violation of the
Act or any applicable state Blue Sky or foreign laws or similar laws relating to
the sale of securities. The Holder further agrees that it will not engage in




                                       6
<Page>

hedging transactions with regard to the Debenture or the shares of Common Stock
issuable upon conversion thereof unless in compliance with the Act.

         7. GOVERNING LAW. This Debenture shall be governed by and construed in
accordance with the laws of the State of New York, without giving effect to the
rules governing the conflicts of laws. The parties hereby irrevocably consent to
the jurisdiction of the courts of the State of New York and of any federal court
located in such state in connection with any action or proceeding arising out of
or relating to this Debenture.

         8. EVENTS OF DEFFAULT. The following shall constitute an "Event of
Default":

            a. The Company fails to make any payment of principal on this
               Debenture as required pursuant to the Debenture and same shall
               continue for a period of fifteen (15) days; or

            b. Any of the representations or warranties made by the Company
               herein or in any certificate or financial or other written
               statements heretofore or hereafter furnished by the Company in
               connection with the execution and delivery of this Debenture
               shall be false or misleading in any material respect at the time
               made; or

            c. The Company fails to issue shares of Common Stock to the Holder
               or to cause its Transfer Agent to issue shares of Common Stock
               upon exercise by the Holder of the conversion rights of the
               Holder in accordance with the terms of this Debenture, fails to
               transfer or to cause its Transfer Agent to transfer any
               certificate for shares of Common Stock issued to the Holder upon
               conversion of this Debenture and when required by this Debenture
               or the Registration Rights Agreement, and such transfer is
               otherwise lawful, or fails to remove any restrictive legend or to
               cause its Transfer Agent to transfer any certificate or any
               shares of Common Stock issued to the Holder upon conversion of
               this Debenture as and when required by this Debenture, the
               Agreement or the Registration Rights Agreement and such legend
               removal is otherwise lawful, and any such failure shall continue
               uncured for fifteen (15) business days after written notice from
               the Holder of such failure; or

            d. The Company shall fail to perform or observe, in any material
               respect, any other covenant, term, provision, condition,
               agreement or obligation of the Debenture and such failure shall
               continue uncured for a period of thirty (30) days after written
               notice from the Holder of such failure; or

            e. The Company shall (1) admit in writing its inability to pay its
               debts generally as they mature; (2) make an assignment for the
               benefit of



                                       7
<Page>

               creditors or commence proceedings for its dissolution; or (3)
               apply for or consent to the appointment of a trustee,
               liquidator or receiver for its or for a substantial part of
               its property or business; or

            f. A trustee, liquidator or receiver shall be appointed for the
               Company or for a substantial part of its property or business
               without its consent and shall not be discharged within sixty (60)
               days after such appointment; or

            g. Any governmental agency or any court of competent jurisdiction at
               the instance of any governmental agency shall assume custody or
               control of the whole or any substantial portion of the properties
               or assets of the Company and shall not be dismissed within sixty
               (60) days thereafter; or

            h. Bankruptcy, reorganization, insolvency or liquidation proceedings
               or other proceedings for relief under any bankruptcy law or any
               law for the relief of debtors shall be instituted by or against
               the Company and, if instituted against the Company, shall not be
               dismissed within sixty (60) days after such institution or the
               Company shall by any action or answer approve of, consent to, or
               acquiesce in any such proceedings or admit the material
               allegations of, or default in answering a petition filed in any
               such proceeding; or

            i. The Company shall have its Common Stock suspended or delisted
               from an exchange for in excess of thirty (30) trading days and
               fail to initiate all steps to quote the Common Stock on the OTC
               Bulletin Board.

Then, or at any time thereafter, and in each and every such case, unless such
Event of Default shall have been waived in writing by a majority in interest of
the Holders of the Debentures (which waiver shall not be deemed to be a waiver
of any subsequent default) at the option of a majority in interest of the
Holders and in the discretion of a majority in interest of the Holders, the
Holder may consider this Debenture immediately due and payable, without
presentment, demand, protest or notice of any kinds, all of which are hereby
expressly waived, anything herein or in any note or other instruments contained
to the contrary notwithstanding, and a majority in interest of the Holders may
immediately enforce any and all of the Holder's rights and remedies provided
herein or any other rights or remedies afforded by law.

         9. PRIORITY, SUBORDINATION. All principal due on this Debenture shall
first be paid in full (hereafter, "PAYMENT IN FULL") in accordance with the
terms hereof before any payment on account of principal of, premium, if any,
interest, dividends or any other amounts shall be made upon any Junior
Securities, whether on account of any purchase or redemption or other
acquisition of such Junior Securities, at maturity or otherwise.

         The Company may make or permit to remain outstanding any indebtedness
or security,



                                       8
<Page>

except that the Company may not issue any securities or indebtedness which are
Senior Securities unless it shall have obtained the consent of not less than
two-thirds of the Holders, whether written or by the vote of such Holders at a
meeting, to incur such indebtedness.

         In the event of (x) any insolvency or bankruptcy proceedings, or any
receivership, liquidation, reorganization or other similar proceedings in
connection therewith, relative to the Company or to its creditors, as such, or
to its assets or (y) the dissolution or other winding up of the Company, whether
voluntary or involuntary and whether or not involving insolvency or bankruptcy
proceedings, or (z) any assignment for the benefit of creditors or any
marshalling of the material assets or material liabilities of the Company (each
a "Liquidation Event"), then, and in any such event, the Holder of this
Debenture shall first be entitled to receive Payment in Full of all principal
due on this Debenture before any payment on account of principal, premium, if
any, interest, dividends or any other amounts is made on the Junior Securities
(as defined below). In the event that upon the occurrence of a Liquidation
Event, the assets available for distribution to the Holder of this Debenture and
the holders of Pari Passu Securities (as defined below) are insufficient to pay
all principal due or to become due on this Debenture and on the Pari Passu
Securities, the entire assets of the Company shall be distributed ratably among
the Holder of this Debenture and the holders of Pari Passu Securities in
proportion to the ratio that the amount so payable on each such security bears
to the aggregate preferential amount payable on all such shares.

         Company "JUNIOR SECURITIES" shall mean all securities and indebtedness
of the Company that are not Pari Passu Securities or Senior Securities as
defined below. "PARI PASSU SECURITIES" shall mean any securities or indebtedness
of the Company that by their terms rank PARI PASSU with this Debenture in
respect of interest, dividends, redemption or distribution upon liquidation,
including all of the other Debentures. "SENIOR SECURITIES" shall mean any
securities or indebtedness of the Company that by their terms have a preference
over this Debenture in respect of dividends, redemption or distribution upon
liquidation. For purposes hereof, the Common Stock and all other capital stock
of the Company shall be deemed to be Junior Securities.

         10. MISCELLANEOUS. Nothing contained in this Debenture shall be
construed as conferring upon the Holder the right to vote or to receive
dividends or to consent or receive notice as a stockholder in respect of any
meeting of stockholders or any rights whatsoever as a stockholder of the
Company, unless and to the extent converted in accordance with the terms hereof.

         No recourse shall be had for the payment of the principal of this
Debenture, or for any claim based hereon, or otherwise in respect hereof,
against any incorporator, stockholder, officer or director, as such, past,
present or future, of the Company or any successor Company, whether by virtue of
any constitution, statute or rule of law, or by the enforcement of any
assessment or penalty or otherwise, all such liability being, by the acceptance
hereof and as part of the consideration for the issue hereof, expressly waived
and released.



                                       9
<Page>

         All payments contemplated hereby to be made "in cash" shall be made in
immediately available good funds in such coin or currency of the United States
of America as at the time of payment is legal tender for payment of public and
private debts. All payments of cash and each delivery of shares of Common Stock
issuable to the Holder as contemplated hereby shall be made to the Holder at the
address last appearing on the debenture register of the Company as designated in
writing by the Holder from time to time; except that the Holder can designate,
by notice to the Company, a different delivery address for any one or more
specific payments or deliveries.

         Upon receipt by the Company of evidence of the loss, theft, destruction
or mutilation of this Debenture, and (in the case of loss, theft or destruction)
of indemnity or security reasonably satisfactory to the Company, and upon
surrender and cancellation of the Debenture, if mutilated, the Company shall
execute and deliver to the Holder a new debenture identical in all respects to
this Debenture.

         If the indebtedness represented by this Debenture or any part thereof
is collected in any proceeding or if this Debenture is placed in the hands of
attorneys for collection after the occurrence of an Event of Default, the
Company shall pay, as an obligation under this Debenture, in addition to the
obligation to pay principal and interest, all costs of collecting this
Debenture, including reasonable attorneys' fees.

         No delay on the part of any party in exercising any right, power or
privilege hereunder shall operate as a waiver thereof, nor shall any waiver on
the part of any party of any right, power or privilege hereunder preclude any
other or further exercise thereof or the exercise of any other right, power or
privilege hereunder.

         All the covenants, stipulations, promises and agreements by or on
behalf of the Company contained in this Debenture shall be binding upon the
Company's successors and assigns whether or not so expressed.

         If any provision of this Debenture is found by a court of competent
jurisdiction to be invalid, illegal or unenforceable, all other provisions of
this Debenture shall remain in effect, and if any provision is in applicable to
any person or circumstances, such provision shall nevertheless remain applicable
to all other persons and circumstances.

         IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed by an officer thereunto duly authorized.

Dated: ________, 20__
                                    ON2.COM INC.

                                    By:
                                        --------------------------------------

                                    ------------------------------------------
                                    (Print Name)

                                    ------------------------------------------
                                    (Title)




                                       10
<Page>

                                    EXHIBIT A


                              NOTICE OF CONVERSION

   (To be Executed by the Registered Holder in order to Convert the Debenture)



         The undersigned hereby irrevocably elects to convert $ ________________
of the principal amount of the above Debenture No. ___ into Shares of Common
Stock of ON2.COM INC. (the "Company") according to the conditions hereof, as of
the date written below.

Conversion Date*

------------------------------------------------------------------

Applicable Conversion Price

------------------------------------------------------------------


Signature

------------------------------------------------------------------
                                    [Name]

Address:

------------------------------------------------------------------

------------------------------------------------------------------


* This original Debenture must be received by the Company or its transfer agent
by the fifth business date following the Conversion Date.



                                       11