Spelvin.
Spelvin, voiced by James Rankin, is a hermit crab who never comes out of his house unless there's something in it for him. In "Petition Impossible", when Iggy and Jiggers were trying to get 200 signatures for the petition to save the Kookamunga from being turned into a highway, they tried to get him to sign. He made them do a ton of work on his house first, took Jiggers' bottle cap collection (which didn't suit with Jiggers), and sent them on their way without signing. In "The Case of the Messy Marauder", Kira mentions that she has written poetry with Spelvin, and that he's pretty good at rhyming.