Mudboy is the eponymous character from the episode Mudboy. Peter makes a drawing in the mud that comes to life. Mudboy likes to have fun but hates boss monsters like Judy. Judy upsets him after he tips the canoe over and he runs away. After Peter reunites with him he leads Peter to a spongy cavern where they bounce around until Mudboy decides to fetch Judy and Alan. He glues Peter to a wall with gooey mud and fetches Judy and Alan.