Petey was Dr. Dilbert Dinkle's evil sidekick in Super Diaper Baby 2: The Invasion Of The Potty Snatchers until Petey betrayed him. He also appeared as the main antagonist of the Dog Man novels, until his redemption in Lord of the Fleas.
Petey is an orange cat with black stripes across his body, pointy ears, long whiskers and a dotted nose.
- Super Diaper Baby 2: The Invasion Of The Potty Snatchers (his first appearance)
- Captain Underpants and the Terrifying Return of Tippy Tinkletrousers - The Adventures of Dog Man (his first defeat by Dog Man)
- Dog Man (book)
- Dog Man: Unleashed
- Dog Man: A Tale of Two Kitties
- Dog Man: and Cat Kid
- Dog Man: Lord of the Fleas (his conversion)
- Dog Man: Brawl of the Wild
- Dog Man: For Whom the Ball Rolls
Prior to Lord of the Fleas, Petey was nasty and teasing. He often picked on Dr. Dilbert and made fun of his plans (and breath). Then, he betrayed him because of how badly Dilbert treated him and tried to destroy the world with Dilbert's Mecha-Kitty robot. He also disliked Dog Man, a referance to cat and dog rivalries. When Super Diaper Baby and Diaper Dog took him to jail, he was excited at first (due to going crazy over the cat litter), but whenever he got arrested thanks to Dog Man, he, almost every time, ends up saying “Rats!”
Petey could get very annoyed by his clone, Lil Peter at times, like when he called him “Papa,” which always ended up in him reminding Lil Petey that he is “NOT [his] PAPA!” He also hated Lil Petey’s jokes about poop and diarrhea, which, any way possible, were absolute nonsense.
In Lord of the Fleas, Lil Petey told Petey to change his ways and be good. Now he has a deep heart for the kitten, and finally accepts being called Papa (although he still gets annoyed by his jokes). But as shown by having a hard time with Big Jim, he is still trying to learn to be as good as Dog Man.