A unique version of Sonic Adventure, “Sonic Adventure Tournament Disk,” has been uncovered by video game preservationist Comby Laurent. This version of the game was specially made for a Sonic Adventure tournament that ran during “The SEGA Dreamcast Mobile Assault Tour,” a 22 week long American promotion that started on August 23 1999. The Assault Tour was a joint event between SEGA of America and IGN that had two Dreamcast-themed trucks traveling across the US, giving some American gamers their first chance to check out SEGA’s new console.

This version of the game drops players right into Emerald Coast with a fully upgraded Sonic, giving them two minutes to get as many points as possible. Participants could win everything from t-shirts, to Japanese VMUs and Millennium 2000-branded Dreamcast controllers. The top 4 finalists were brought to Las Vegas at the end of the tour, where they could complete for a $15,000 grand prize. The second and third place winners received $5000 and $2500 respectively, while the fourth place winner got some SEGA swag.

While this is mostly notable for being a special version of Sonic Adventure from an obscure part of SEGA’s history, it’s also a very-late prototype build of the game. It’s dated August 10, 1999, just two days before the final build on August 12. As a result, the differences between this build and the final are minor, only lacking music for the DLC and a fully completed European localization.

If you want to read more about this game and the event, or play what those contestants did decades ago, you can find the dump of this unique, once lost piece of history on Laurent’s website, here. You can check out a recording of the game in action in Laurent’s original tweet below: