The Pest / The Sale

S4 E104: The Pest: When they find Anais training herself for a brutal showdown, Gumball and Darwin realize that their sister is being pestered at school by an annoying kid: Billy. They try to teach her how to resolve the problem peacefully, but Billy has other ideas. / The Sale: Gumball and Darwin are devastated to learn that Mr. Robinson -- their favorite person in the world -- is selling his house and leaving town. When they realize that making some final happy memories with Mr. Robinson is not enough for them, they decide to stop him leaving... by sabotaging the sale.