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-colour illustrations throughout!