when they put a diaper on him and rename him Diaper Dog. Meanwhile, back at the power plant, radioactivity causes Deputy Doo-Doo to grow into a giant and he resumes rampaging through the city. Diaper Baby and Diaper Dog fly out to stop him, but since Deputy Doo-Doo's now radioactive, they can't touch him. They instead trick him into attacking himself and wrap him up in a giant toilet roll, sending him to Uranus. On the way back to Earth, at a "Starbutts" on Mars, they decide to take some Super Power Juice back to Earth and go to the laundromat where Captain Underpants is held captive. They restore his powers, and the world is a better place. Characters Billy Hoskins/Super Diaper Baby – the book's protagonist; he is a newborn baby who gains Captain Underpants' powers. Danger/Diaper Dog – the Hoskins' pet puggle and Super Diaper Baby's sidekick. He was once allied with Deputy Dangerous, but only because the villain gave him ample "kibbles". He gained superpowers by drinking half of the liquid produced by Deputy Dangerous' power-draining ray. Deputy Dangerous/Doo-Doo – the main antagonist of Book 1. He becomes a piece of poop due to a mishap in one of his attempts to steal Super Diaper Baby's powers and grows huge when he gets dumped in radioactive waste. Billy and Diaper Dog wrap him with a giant toilet paper from Bob's Toilet Paper Store and take him to Uranus, never to be heard from again. Dr. Dilbert Dinkle/Rip Van Tinkle – the main antagonist of Super Diaper Baby 2. He once was a criminal/inventor, now shunned everywhere due to his stench, as simple water-turned-urine. Dav Pilkey originally planned to name Tinkle "Pee Pee Longstockings". While attacking a giant pee-formed Dr. Dinkle, Billy and Diaper Dog push the Earth far away from the sun, making it snow and Dr. Dinkle freezes solid. Petey – a grumpy tabby cat. Petey dislikes Rip Van Tinkle's attitude and bad breath. He is the controller of the Robo Kitty and Supa - Mecha Kitty 3000. He appeared in Book 2, as well as the Dog Man novels. Additional characters Bill and Mary Hoskins - Billy's parents. Captain Underpants - George and Harold's Waistband Warrior. In Book 1, he made a special appearance, where he enters Deputy Dangerous's trap, designed as an underwear cleaner, and the Deputy zaps his powers, turning them into a