Edna Krabappel is Bart's fourth grade teacher on the show The Simpsons.  Edna is voiced by Marcia Wallace and is portrayed as a lonely divorcee.  She previously dated Skinner, but now mostly will throw herself at anything that's remotely willing.

Edna Krabappel Quotes

(Bart shows the whole classroom the tape for his project called, "How Kittens Are Born: The Ugly Truth")
Bart: and here comes Snowball II. This is the one we kept.
All: EWW!!
Bart: We were gonna keep the gray one, but the mother ate her.
Martin: Mrs. Krabappel, he's traumatizing the children!
Mrs. Krabappel: As usual, I agree with you, Martin. Bart, shut that off and take your seat immediately!
Bart: Oh, look! This is really cool. When I hit reverse, I can make 'em go back in.
(The whole classroom screams)

Now, I don't want you to worry class. These tests will have no affect on your grades. They merely determine your future social status and financial success. If any.

Mrs. Krabappel

The Simpsons Quotes

Homer: (Wearing glasses) The sum of the square roots of any two sides of an isosceles triangle is equal to the square root of the remaining side!
Man: (From inside a bathroom stall.) That's a right triangle, you idiot!
Homer: D'oh!

Yep, here's your problem. Someone set this thing to "Evil."