Mr. Krupp
Mr Krupp is the horribly mean princepal of the elementary school that George and Harold go to. By day he is a normal horribly mean princepal, but when he hears a snap of the fingers he turns into Captain Underpants(for George and Harold hypnotized Mr. Krupp with a hypno ring they bought out of the back of a comic book in the first Captain Underpants novel The Adventures of Captain Underpants.)
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