Sandworm

Sandworm, called Nal (ナール) in the Japanese Manual, is a caterpillar badnik from Sonic & Knuckles found in the quicksands of Sandopolis Zone. They swim around in the quicksand and jump out of it to attack the player. They are very similar to the Caterkiller in terms of appearance, including having the same name in Japanese (as well as using the same sprite sheet (albeit with a different color palette)), but their behavior is different. (They jump back and forth out of sand pits, unlike the Caterkiller badnik.) But just like the Caterkillers, they can only be destroyed by jumping on their noggins.