Sonic the Hedgehog Chaos is a 1993 platform game developed by Aspect and published by Sega for the Master System and Game Gear. Players control Sonic the Hedgehog and his sidekick Miles "Tails" Prower in their quest to retrieve the Chaos Emeralds from Doctor Robotnik, who has stolen them to construct nuclear weapons. Gameplay involves running through stages, collecting rings, and defeating enemies. It is largely based on the Master System version of Sonic the Hedgehog 2, and is thus considered a follow-up to that game.