Knuckles' Chaotix (First and only appearance)
Powering Robotnik's machines
Small versions of Dark Rings are seen throughout the game after the player destroys a Badnik, similar to Sonic Advance 3, but the rings can't be collected. Every boss in the game is shown to be powered by a Dark Ring, the container of which usually serves as a weak spot. Although the Dark Rings are very powerful, they disintegrate once they leave the object they are powering.