Lt. Nibbles is the gerbil mascot of the Quahog Police force in "Cop and a Half-Wit". Joe finds himself having to take care of him, noting that he'll only eat deluxe cheese, not processed. When Questioned by the guys, Joe admits that the gerbil outranks him.
When Peter takes down a drug ring despite violating several police protocols with Joe, Joe is congratulated by both the Captain and Lt. Nibbles, who are unaware of Peter's participation.