From Dav Pilkey, creator of Captain Underpants, and acclaimed artist Dan Santat, an out-of-this-world friendship adventure with all-new full-color illustrations! Ricky Ricotta is lucky to have his Mighty Robot as a best friend. They play, study, and even get in trouble together, and they always watch out for each other. That's what friends are for! In this book, Ricky and his Mighty Robot meet a mean little Martian named Major Monkey who plans to take over Earth with his monstrous Mecha-Monkeys. When Major Monkey plays a trick on Ricky's Robot, it's up to Ricky to rescue his friend and stop Major Monkey from menacing mousekind! Originally published in 2002, this edition features brand-new full-color illustrations and mini-comics throughout!