Sonic Rivals is a 2006 action-racing video game developed by Backbone Entertainment and Sega Studio USA, and published by Sega for the PlayStation Portable (PSP); it is a game in the Sonic the Hedgehog series, and follows the heroes needing to stop Doctor Eggman Nega from turning everyone and the world into cards. The gameplay involves racing against other characters to get to the goal before them, as well as defeating the boss before the opponent does.