He is a light pink worm with a large nose that is a darker shade of pink. He also seems to have some little hairs sprouting out of his nose. His eyes are a shade of light yellow and he has black pupils as well.
In the short, "Clam up!", Prickle's story begins at his house. A clam irritates him so he ships it away. However, the clam attacks the mailman and attempts to kill Prickles. To protect himself, he squirms up SpongeBob's house into his window and then crawls over.
Prickles is the first worm to move into SpongeBob's body. He moves in during the night and gains acceptance of occupation from SpongeBob through a sob story, meaning that he is able to stay. He calls in other worms, and start throwing a party. SpongeBob wakes up and joins in, until he realizes it is time to go to work.
The worms cause a lot of distress for SpongeBob, as he is kicked out of his house by Gary and is fired from his job. They all leave his body after they are driven away by his annoying laughter. They enter Squidward's house and start living there, much to his dismay.