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. 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?