Captain Underpants and the Big Bad Battle of the Bionic Booger Boy, Part 2 by Dav Pilkey
Just when George and Harold thought they'd saved the world again - oh no! Here come the Robo-Boogers! Disgusting and dangerous hi-tech robots made of gloomy SNOT. It's lucky that our heroic Waistband Warrior Captain Underpants is standing by, with the power of underwear on his side and his hankie to hand!