Miss Simian

Miss Simian is Gumball's sadistic teacher, who has been teaching second grade for 300,000 years. She utterly despises Gumball and does whatever she can to foil his plans. Principal Brown is hopelessly in love with her, and she returns the feeling, as shown in The Mystery, where she says "My poor, sweet Nigel!", and in The Party where they're seen crashing a party and kissing in the end of the episode. She was also portrayed as the main antagonist in The Mystery.

She likes to give out tests as shown in The End. She also seems to like pretty dresses, though it may just be the dress' powerful effect of beauty that causes her to like it. She is Gumball's arch-enemy.