Michael Fry 
Odd Squad: Bully Bait [EPUB ebook] 

Nick is stuffed in his locker. Again. It's not so bad. Lockers are roomier than you'd think. Especially when you're the shortest kid on the planet, which is exactly why Bully-Boy Roy stuffed him in there in the first place: he fits. The school counselor says Roy has issues. The only issue Nick can see is that Roy is a mutant troll. Nick's friends Molly and Karl think the troll needs to be defeated. Together, they are THE ODD SQUAD. If you want to laugh out loud, watch them beat the bullies and see some cool pictures, READ THIS BOOK!