Crab Teacher is an archenemy of Stupendous Man, an alter ego of Calvin. She is actually an alter ego of Miss Wormwood, Calvin's teacher. When Calvin's class writes history test, Calvin brings his Stupendous Man's costume and hides it in his locker. During the test, he asks Miss Wormwood to get a drink of water, enters his locker and wears the costume, becoming Stupendous Man himself. Unfortunately, he accidentally locks himself in the locker. Meanwhile, Crab Teacher leaves the classroom to look for him. She opens Calvin's locker and Stupendous Man jumps out, ready for fight. However, Crab Teacher grabs his hand to take to the psychologist. Stupendous Man eventually escapes, runs into the classroom, writes Calvin's test and leaves. Later, Miss Wormwood enters the classroom, looking for Calv