When George and Harold hypnotize their principal into thinking that he is the superhero Captain Underpants, he leads them to the lair of the nefarious Dr. Diaper, where they must defeat his evil robot henchmen.

When Harold and George turn fourth-grade teacher Ms. Ribble into the evil Wedgie Woman, she gives the wedgie of doom to unsuspecting people who stand in her way--including principal-turned-superhero Captain Underpants.

Captain Underpants's spookiest--and stretchiest--adventure yet! George Beard and Harold Hutchins are back in a new Halloween adventure! Piqua's biggest pranksters are getting ready for the best holiday ever--Halloween, of course. But their dreams of costumes, candy, and haunted houses go down the drain when Mr. Krupp and Melvin start a campaign to make Halloween illegal! That's when George and Harold come up with HACK-A-WEEN, a totally legal spin-off...