With Mr. Krupp gone and two terrible Melvins in charge, Harold and George fight back by hypnotizing their gym teacher, Mr. Meaner.

The boys recruit kids to join the M.I.S.F.A.R.T.S. -- the Mega Incredible Search Force Adventure Rescue Team Squad -- and bring Mr. Krupp back to School.

After injecting all the teachers with bee DNA, the Melvins run the new "hive mind" of the school -- until Ms. Ribble accidentally becomes queen bee.

George and Harold train a rat for extra credit. But when their subject escapes into the sewers, he's doused with toxic waste and becomes ... Poopacabra!

Who knew a thawed-out dinosaur could read comics and pull pranks? Well, this one does -- and he's one of Harold and George's biggest fans.

Captain Underpants becomes a wanted man when a criminal who looks just like him starts robbing banks. Can George and Harold help clear his name?

The boys use Melvin's new animal hybrid invention to make a creature that's a cross between a butt and a fly. But these butt-erflies are real monsters!

After George and Harold work with Erica to create a new comic hero, she springs off the page -- and plunges into real-life crime fighting.

The boys transfer to a bizarro version of Jerome Horwitz Elementary, where the teachers are nice, the kids are good ... and fun is nowhere to be found.

George and Harold trick Melvin into turning their bus into a time machine so they can reroute their field trip and see what ancient Rome was really like.

The Melvins' latest invention sends the boys' Dump Day "trash-alanche" into another dimension -- and inadvertently summons a monster.

A final exam sends George and Harold to the Doom Dome, where they must battle Melvin -- who's been injected with powerful nanobots -- in order to pass.

Summer camp is on the line as Melvin's nanobots find a new host in Captain Underpants, forcing the boys to shrink down and go inside his brain.