From the co-creator of the #1 New York Times bestselling Spiderwick Chronicles series comes a deliciously dark supernatural middle-grade coming-of-age story, with two-color illustrations throughout.

“Terrifyingly terrific.”—Jeff Kinney, New York Times bestselling creator of the Diary of a Wimpy Kid series

Timothy’s grandpa has a saying: the best way to deal with bullies is to wump ‘em. But Timothy would never hurt a fly—and not just because he genuinely loves bugs. He’s always been a good kid…until a shadowy monster appears and begins feeding on his darkest thoughts. Facing bullies both at home and at school, Timothy cocoons himself in the monster’s shadows, where he is consumed by a desire for revenge. But how much of himself can Timothy give up before he is completely transformed?

Award-winning author-illustrator Tony DiTerlizzi stuns in this creepy, brilliantly illustrated, and poignant reflection of the darkness—and light—inside of all of us.