Dog Man: Lord of the Fleas (Dog Man #5) by Dav Pilkey

When a fresh bunch of baddies bust up the town, Dog Man is called into action -- and this time he isn't alone. With a cute kitten and a remarkable robot by his side, our heroes must save the day by joining forces with an unlikely ally: Petey, the World's Most Evil Cat. But can the villainous Petey avoid vengeance and venture into virtue?

Dav Pilkey's wildly popular Dog Man series appeals to readers of all ages and explores universally positive themes, including empathy, kindness, persistence, and the importance of being true to one's self.