SEGA Illusion is is a racecourse in Sonic Riders. Not part of the game's main Story Mode, the track features simply as an extra level for Free Play, although there are 5 tasks to complete in Mission Mode too. It is unlocked by earning a Gold Emblem in the Babylon Cup in Grand Prix Mode.
A night-time analogue of SEGA Carnival, SEGA Illusion's course theme is also pieced together from several other SEGA game franchises. Enemies based on Fantasy Zone's Opa-Opa patrol the start of the course amidst bopping townhouses from Samba de Amigo, before the racers pass into a winding NiGHTS-themed concourse. Mini-zeppelins from Space Channel 5 drop you off at a spaceport, and finally the characters have to navigate an arrowed board from ChuChu Rocket!.