The pet of Knuckles the Echidna, Chomps is a carnivorous dinosaur with a blue underside and the top of his body being red. Chomps is the only other known inhabitant of Sonic Underground's Floating Island, and served Knuckles by devouring intruders who came onto the island. He wanted to eat Sleet and Dingo, but after Knuckles released them they ran away, leaving behind a holo-projector with falsified images of Sonic, Sonia, and Manic planning to steal the Chaos Emerald. Chomps ate the projector, causing the images to appear out of his mouth and nostrils. Thanks to this, the Hedgehogs were able to determine why Knuckles was attacking them. Chomps only appeared in the episode Friend or Foe.
Interestingly, Chomps bears some resemblance to the Biolizard - though of course Chomps was made long before the idea of the Biolizard was even conceived.