Believe it or not, the Captain Underpants books are almost 20 years old.
Utilizing hypnosis, they convince Krupp that he is actually a superhero of their own creation, Captain Underpants, who battles supervillains wearing only a pair of white briefs and a cape.
Written and illustrated by Pilkey, the Captain Underpants books (there are 12 in total) revolve around a pair of elementary school best friends named George Beard and Harold Hutchins, whose antics lead to them being menaced by their mean, overbearing school principal Mr. Krupp.
Over the course of the books, Krupp (who is unaware of his dual personality) acquires superhuman powers of his own and “transforms” against his will when someone snaps their fingers or he is doused with water.