Leonard

Leonard is one of Roofus' sons found in the Quackenheim Museum.

How to Rescue in Fur Fighters (Dreamcast)
Near the vault is a Roofus Telepoint. Switch to him and backtrack to the previous room and climb the ladder. Wind around the corner and you'll find Leonard.

How to Rescue in all other Versions
He is stuck inside a glass cabinet behind a set of bowling pins in this version. If the Fur Fighters get to the top of the stairs, they can tap the bowling ball, which in turn knocks the pins over on the ground floor and frees Leonard. Switch to Roofus and save him.