Subsequent Events	12 Months Ended
Sep. 30, 2025
Subsequent Events [Abstract]
Subsequent Events	Note 10 — Subsequent Events The Company evaluated subsequent events and transactions that occurred after the balance sheet date through the date when these audited consolidated financial statements were issued. Based on this review, the Company identified the following subsequent events that would require adjustment or disclosure in the financial statements. Proposed Business Combination with Marine Thinking On October 29, 2025, the Company entered into the BCA with Marine Thinking, an autonomous ship and fleet solution providing company incorporated under the CBCA and Amalgamation Sub. The BCA contemplates that the business combination among Eureka, Marine Thinking and Amalgamation Sub will be completed through the following series of transactions, (i) prior to the Amalgamation Effective Time, Eureka shall complete the deregistration as a Cayman Islands exempted company in accordance with section 206 of the Companies Act and, immediately upon such deregistration, the domestication to Canada under the CBCA. Upon the completion of the SPAC Continuance, the name of Eureka shall be changed from “Eureka Acquisition Corp” to “Marine Thinking Holdings Inc.” or such other name as the Parties may agree on; and (ii) following the SPAC Continuance, and in accordance with the applicable provisions of the BCA and in accordance with the CBCA, at the Closing, Marine Thinking and the Amalgamation Sub shall amalgamate and continue as one company, being Amalco, under the terms and conditions prescribed in the amalgamation agreement to be signed by Marine Thinking and Amalgamation Sub and in accordance with section 181 of the CBCA. Following the Amalgamation Effective Time, Amalco will become a direct wholly owned subsidiary of Eureka. Support Agreement Concurrently with the execution of the BCA, the Sponsor, Eureka and Marine Thinking have entered the Support Agreement pursuant to which, among other things, the Sponsor agreed to (i) vote, or cause to be voted or consented at any meeting of the shareholders of Eureka, or in any action by written consent of the shareholders, all of its Sponsor Shares, (a) in favor of the approval and adoption of the BCA and the Transactions contemplated thereby, and any other matter reasonably necessary to the consummation of the Business Combination, and (b) against the proposals in connection with other alternative business combinations other than the Business Combination with Marine Thinking; and (ii) not to transfer any Sponsor Shares until the Expiration Time (as defined in the Support Agreement). Voting Agreement Concurrent with the execution and delivery of the BCA, Marine Thinking, Eureka, the Amalgamation Sub and the Requisite Shareholders have entered into the Voting Agreement, pursuant to which the Requisite Shareholders agreed to, among other things, (i) vote, or cause to be voted or consented at a meeting of the Target Shareholders, or in any action by written consent of the shareholders, all the Subject Shares, (a) in favor of the approval and adoption of the BCA and the Transactions contemplated thereby, and any other matter reasonably necessary to the consummation of the Business Combination, and (b) against the proposals in connection with other alternative business combinations other than the Business Combination with Eureka; and (ii) not to transfer any Subject Shares until the Expiration Time (as defined in the Voting Agreement). Registration Rights Agreement The BCA contemplates that, at the Closing, Eureka, the Sponsor, each of the Target Shareholders and certain other parties named therein will enter into the Registration Rights Agreement, pursuant to which Eureka will agree to register for resale, pursuant to applicable securities laws and regulations, with respect to the registrable securities held by the Holders (as defined in the Registration Rights Agreement). Lock-Up Agreements The BCA contemplates that at the Closing, each of the Sponsor and certain of the Target Shareholders will enter into a Lock-up Agreement, pursuant to which (i) the Sponsor agrees on certain restrictions on transfer of SPAC Class B Shares (as defined in the BCA) held by the Sponsor immediately prior to the Closing; and (ii) certain of the Target Shareholders agree on certain restrictions on transfer of SPAC Shares held by them immediately after the Closing, including any shares issuable upon the exercise of any rights, options, warrants or other securities to purchase any SPAC Shares held by them immediately after the Closing, or any rights, options, warrants or other securities convertible into or exercisable or exchangeable for any SPAC Shares held by them immediately after the Closing. The lock-up period commences on the Amalgamation Effective Time and continues until the earlier of (i) three-hundred and sixty-five (365) days after the Closing, or (ii) the date on which Eureka completes a liquidation, merger, capital stock exchange, reorganization or other similar transaction that results in all of Eureka’s shareholders having the right to exchange their SPAC Shares or other equity securities of Eureka for cash, securities or other property. Term Extensions On October 31, 2025 and December 2, 2025, the Company deposited the Monthly Extension Fee of $150,000 each time into the Trust Account for the public shareholders, which enables the Company to extend the period of time it has to consummate its initial business combination by two months from November 3, 2025 to January 3, 2026.. On November 4, 2025 and December 4, 2025, the Company issued two Extension Notes to the Sponsor, each representing an aggregate principal amount of $150,000, in connection with the payment of Monthly Extension Fee. Each Extension Note bears no interest and is payable in full upon the earlier to occur of (i) the consummation of the Company’s Business Combination or (ii) the date of expiry of the term of the Company. The Sponsor, has the right, but not the obligation, to convert the Extension Note, in whole or in part, respectively, into Conversion Units, each consisting of one Class A ordinary share, par value $0.0001 per share and one right to receive one-fifth (1/5) of one Class A ordinary share upon the consummation of a Business Combination. The number of Extension Units to be received by the Sponsor in connection with such conversion shall be an amount determined by dividing (x) the sum of the outstanding principal amount payable to the Sponsor by (y) $10.00.

Subsequent Events

12 Months Ended

Sep. 30, 2025

Note 10 — Subsequent Events

The Company evaluated subsequent events and transactions that occurred after the balance sheet date through the date when these audited consolidated financial statements were issued. Based on this review, the Company identified the following subsequent events that would require adjustment or disclosure in the financial statements.

Proposed Business Combination with Marine Thinking

On October 29, 2025, the Company entered into the BCA with Marine Thinking, an autonomous ship and fleet solution providing company incorporated under the CBCA and Amalgamation Sub.

The BCA contemplates that the business combination among Eureka, Marine Thinking and Amalgamation Sub will be completed through the following series of transactions, (i) prior to the Amalgamation Effective Time, Eureka shall complete the deregistration as a Cayman Islands exempted company in accordance with section 206 of the Companies Act and, immediately upon such deregistration, the domestication to Canada under the CBCA. Upon the completion of the SPAC Continuance, the name of Eureka shall be changed from “Eureka Acquisition Corp” to “Marine Thinking Holdings Inc.” or such other name as the Parties may agree on; and (ii) following the SPAC Continuance, and in accordance with the applicable provisions of the BCA and in accordance with the CBCA, at the Closing, Marine Thinking and the Amalgamation Sub shall amalgamate and continue as one company, being Amalco, under the terms and conditions prescribed in the amalgamation agreement to be signed by Marine Thinking and Amalgamation Sub and in accordance with section 181 of the CBCA. Following the Amalgamation Effective Time, Amalco will become a direct wholly owned subsidiary of Eureka.

Support Agreement

Concurrently with the execution of the BCA, the Sponsor, Eureka and Marine Thinking have entered the Support Agreement pursuant to which, among other things, the Sponsor agreed to (i) vote, or cause to be voted or consented at any meeting of the shareholders of Eureka, or in any action by written consent of the shareholders, all of its Sponsor Shares, (a) in favor of the approval and adoption of the BCA and the Transactions contemplated thereby, and any other matter reasonably necessary to the consummation of the Business Combination, and (b) against the proposals in connection with other alternative business combinations other than the Business Combination with Marine Thinking; and (ii) not to transfer any Sponsor Shares until the Expiration Time (as defined in the Support Agreement).

Voting Agreement

Concurrent with the execution and delivery of the BCA, Marine Thinking, Eureka, the Amalgamation Sub and the Requisite Shareholders have entered into the Voting Agreement, pursuant to which the Requisite Shareholders agreed to, among other things, (i) vote, or cause to be voted or consented at a meeting of the Target Shareholders, or in any action by written consent of the shareholders, all the Subject Shares, (a) in favor of the approval and adoption of the BCA and the Transactions contemplated thereby, and any other matter reasonably necessary to the consummation of the Business Combination, and (b) against the proposals in connection with other alternative business combinations other than the Business Combination with Eureka; and (ii) not to transfer any Subject Shares until the Expiration Time (as defined in the Voting Agreement).

Registration Rights Agreement

The BCA contemplates that, at the Closing, Eureka, the Sponsor, each of the Target Shareholders and certain other parties named therein will enter into the Registration Rights Agreement, pursuant to which Eureka will agree to register for resale, pursuant to applicable securities laws and regulations, with respect to the registrable securities held by the Holders (as defined in the Registration Rights Agreement).

Lock-Up Agreements

The BCA contemplates that at the Closing, each of the Sponsor and certain of the Target Shareholders will enter into a Lock-up Agreement, pursuant to which (i) the Sponsor agrees on certain restrictions on transfer of SPAC Class B Shares (as defined in the BCA) held by the Sponsor immediately prior to the Closing; and (ii) certain of the Target Shareholders agree on certain restrictions on transfer of SPAC Shares held by them immediately after the Closing, including any shares issuable upon the exercise of any rights, options, warrants or other securities to purchase any SPAC Shares held by them immediately after the Closing, or any rights, options, warrants or other securities convertible into or exercisable or exchangeable for any SPAC Shares held by them immediately after the Closing. The lock-up period commences on the Amalgamation Effective Time and continues until the earlier of (i) three-hundred and sixty-five (365) days after the Closing, or (ii) the date on which Eureka completes a liquidation, merger, capital stock exchange, reorganization or other similar transaction that results in all of Eureka’s shareholders having the right to exchange their SPAC Shares or other equity securities of Eureka for cash, securities or other property.

Term Extensions

On October 31, 2025 and December 2, 2025, the Company deposited the Monthly Extension Fee of $150,000 each time into the Trust Account for the public shareholders, which enables the Company to extend the period of time it has to consummate its initial business combination by two months from November 3, 2025 to January 3, 2026..

On November 4, 2025 and December 4, 2025, the Company issued two Extension Notes to the Sponsor, each representing an aggregate principal amount of $150,000, in connection with the payment of Monthly Extension Fee. Each Extension Note bears no interest and is payable in full upon the earlier to occur of (i) the consummation of the Company’s Business Combination or (ii) the date of expiry of the term of the Company. The Sponsor, has the right, but not the obligation, to convert the Extension Note, in whole or in part, respectively, into Conversion Units, each consisting of one Class A ordinary share, par value $0.0001 per share and one right to receive one-fifth (1/5) of one Class A ordinary share upon the consummation of a Business Combination. The number of Extension Units to be received by the Sponsor in connection with such conversion shall be an amount determined by dividing (x) the sum of the outstanding principal amount payable to the Sponsor by (y) $10.00.