"Bart Gets a 'Z'" is the second episode of the twenty-first season of the American animated television series The Simpsons. It originally aired on the Fox network in the United States on October 4, 2009. In the episode, the fourth grade students of Springfield Elementary School decide to spike Edna Krabappel's coffee in order to teach her a lesson after she takes away their cell phones. She is fired by Principal Skinner, who hires a new teacher named Zachary Vaughn. Although Vaughn is a hip young teacher who impresses the students, Bart is plagued by guilt and tries to get Edna hired back.