Sonic & All-Stars Racing Transformed is a 2012 kart racing game developed by Sumo Digital and published by Sega, featuring characters from various Sega franchises. Its core mechanic is the transforming vehicles that shift between car, boat, and plane modes to adapt to dynamic, changing tracks. The game offers a variety of modes, including single-player, online multiplayer, and special challenges, all set on courses inspired by Sega's history.