He is a huge slug-like monster with dark-green skin, red spots, six yellow eyes, three fingers with sharp fingernails on his hands, six tentacles for legs, spikes on his back, a mouth on each palm of his hands, a long tail with a stinger, pointy teeth, and light-green fins.
The monster first appears when it stars attacking everyone in the Krusty Krab after it was blown away from a rip current. SpongeBob attempts to make Squidward fight the monster, but Squidward ends up getting eaten instead. However, after convincing Mr. Krabs to resume his duties as captain, Mr. Krabs fights the monster and makes him spit Squidward out.
The monster is defeated when Mr. Krabs sends it colliding with a boulder and breaks into tiny monsters. The tiny monsters then scatter away, never to be seen again.