Diaper Dog (formerly known as Danger Dog) is Super Diaper Baby's sidekick. He defeated Deputy Doo-Doo and Rip Van Tinkle with him. Diaper Dog is Super Diaper Baby's best friend and pet who shares the same powers as him. His heroic, helpful, clever and obedient personality is a big help to him and Billy Hoskins when they're fighting crime and the forces of evil.
Diaper Dog was originally Deputy Dangerous' sidekick and partner, Danger Dog. One day, the evil cowboy attempted to kill his nemesis, Billy Hoskins (Super Diaper Baby). Diaper Dog rescues his new pal and they return home, where the landlord makes the new hero wear a diaper for the time being so he doesn't "Go Pee Pee on the carpet".
Diaper Dog appears along side Super Diaper Baby in every book he appears in.
- Danger Dog was originally going to wear a dark red cape but the idea was scrapped for unknown reasons.
- Danger Dog makes a joke about Deputy Doo Dooo that was referring to Disney's Winnie The Pooh.
- Diaper Dog has pink fur which might be his skin.
- He makes an appearance as a doll in Super Silly Streak, an online video on Dav Pilkey' s websites
- Him and Super Diaper Baby are the stars of the animated musical short, "Super Diaper Baby Country Shuffle".
- Diaper Dog is the only super powered animal created by David "Dav" Pilkey in all his work.