A Guard Worm is a large, violent worms that guard various places in Bikini Bottom. One is first seen in The Lost Mattress, where it was living in the dump, at the moment on Mr. Krabs' misplaced money filled matrress, where Squidward was violently mauled by it various times. Another one was seen in the episode BlackJack when SpongeBob's cousin BlackJack had one guarding his front entrance. In Best Frenemies one was guarding the KelpShake store, on the night Krabs and Plankton tried to steal the KelpShake's formula. There are various Worms that work for the Bikini Bottom Police Force. They are Green and have Silver spiked collars.
- The worms are possibly a parody of Rottweilers or Dobermans because of their vicious features.