Holy guacamole! George and Harold are so determined to win an avocado-growing contest that they accidentally turn their science teacher into a monster.
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.
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!
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!
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.
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.