Lucy 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 appears to return 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.

As shown in The Party, she likes to have a good party. She doesn't seem to appreciate "boring" ones at all, and prefers a more crazy party.

Appearance
Miss Simian is a very, very old baboon. She has dark grey fur, and a homely primate face. She usually wears a pale brownish-red and yellow polka-dotted dress. Her body shape is similar to that of a baboon standing upright, her knuckles dangle very low to the floor, and she is very skinny. Her voice is raspy and cold, and she intimidates most of her students with her grumpy and uncaring attitude.

Name
The word "simian" in Miss Simian's name means monkey, which is accurate since Miss Simian is a baboon. The "miss" in her name indicates that she is not married.

Students
As Miss Simian is a teacher, she teaches these students. These are her possible dislikes and favorites: Masami does not seem to be in Miss Simian's classroom, despite knowing that a "beautiful girl" was in Miss Simian's classroom in The Dress. Anais does not seem to be in Miss Simian's class either, possibly due to the fact that she skipped 6th because she was a prodigy.
 * Gumball Watterson (dislike)
 * Darwin Watterson (dislike)
 * Idaho (favorite)
 * Tina Rex (dislike, due to Tina mostly wrecking the school)
 * Alan (dislike)
 * Molly (favorite)
 * Tobias (dislike)
 * Carrie (favorite)
 * Penny (favorite)
 * Banana Joe (dislike)
 * Leslie (favorite)
 * Anton (dislike)
 * Teri (favorite)
 * Bobert (dislike, as shown in "The Mystery")
 * Sussie (dislike, possibly due to her rude behavior )

Quotes
Miss Simian: "Like a baby!"
 * "You get an F minus -- in parenting!"
 * "Are you aware that your husband isn't wearing any pants?"
 * "Next! Oh, the Wattersons..."
 * "You're not trying to cheat, are you, Gumb-- huh?mmm... Who are you?"
 * "...while the rest of us get on with class!"
 * "GET HIM!!"
 * "I have a surprise for you, children -- a surprise test! Hahahaha!"
 * Gumball: "How do you sleep at night, Miss Simian?"
 * A secret house party, eh?, hmm, I better tell Principal Brown.
 * "This party is busted!"

Trivia

 * Miss Simian is one of many characters to be created in CGI.
 * Like most cartoon characters, Miss Simian has four fingers, while real apes have five.

Principal Brown
Principel Brown is in love with Miss Simian and it is strongly hinted that she is in love with him too.