By Andy Griffiths
A boy's own bottom runs away from home to join an army of butts plotting to take over the world.
One night Zack Freeman's butt detaches itself and sneaks off. It turns out this happens all the time, and runaway butts are gathering in the desert into a giant stinky army with a plan to take over the world. So Zack has to go after his own butt to stop the whole thing. It's a real action-adventure quest, chases and all, except every bit of it runs on fart jokes and butt puns, and the title tells you exactly what you're in for.
This is a step up in length from a comic-heavy book, real chapters and a couple hundred pages, but a child barely notices because the whole thing is one long fart joke wearing an adventure costume. The gross-out is the engine that pulls them through actual paragraphs. For the exact child who groans at reading, the title alone is a dare they can't turn down, and finishing a book this thick because they wanted to is a genuine milestone.