Butt Trilogy Series by Andy Griffiths, Miles Thompson

Zack Freeman is ready to tell his story—the story of a brave young boy and his crazy runaway butt. The story of a crack butt-fighting unit called the B-team, a legendary Butt Hunter's formidable daughter, and some of the ugliest and meanest butts ever to roam the face of the Earth... moreZack Freeman is ready to tell his story—the story of a brave young boy and his crazy runaway butt. The story of a crack butt-fighting unit called the B-team, a legendary Butt Hunter's formidable daughter, and some of the ugliest and meanest butts ever to roam the face of the Earth. A story of endurance that takes Zack on an epic journey across the Great Windy Desert, through the Brown Forest, and over the Sea of Butts before descending into the heart of an explosive butt-cano to confront the biggest, ugliest, and meanest butt of them all!It's a story you and your butt will never forget! less

An alien army of killer mutant zombie bums is headed for Earth. Their mission? Total zombie-bummification of the planet. Who else could be behind a plan to stink out the entire solar system but the Great White Bum? Luckily, the dastardly derriere holds no fear for Zack.

The stinky scoundrels from international bestsellers THE DAY MY BUTT WENT PSYCHO! and ZOMBIE BUTTS FROM URANUS! are back--and determined to wipe away the earth!Zack Freeman (and his butt) have twice saved the world from total reek-dom. But now the young butt-fighter faces his nastiest challenge yet: Hundreds of thousands of Great White Butts attacking the earth with giant brown blobs are about to cause Buttageddon... moreThe stinky scoundrels from international bestsellers THE DAY MY BUTT WENT PSYCHO! and ZOMBIE BUTTS FROM URANUS! are back--and determined to wipe away the earth!Zack Freeman (and his butt) have twice saved the world from total reek-dom. But now the young butt-fighter faces his nastiest challenge yet: Hundreds of thousands of Great White Butts attacking the earth with giant brown blobs are about to cause Buttageddon. In order to stop them, Zack will have to hitch a ride in a time-traveling buttmobile, back to the reign of the prehistoric buttosaurs. Can Zack battle the Tyrannosore-arses, juggle a giant arseteroid, and put the butts-gone-bad back in their place? Or will the entire world be abutterated? less