The Simpsons (1989): Season 18, Episode 20

18 - 20: Stop or My Dog Will Shoot

Homer is upset when he realizes that Marge brought him and the family to a boring Harvest Fest instead of his much-anticipated day of debauchery at October Fest. Attempting to leave, Homer accidentally drags the family into a puzzling cornfield maze. When the whole family manages to escape except for Homer, they send out Santa's Little Helper, who sniffs out Homer and rescues him. Santa's Little Helper becomes a local hero and the Simpsons decide to enroll him in Police Dog Academy, where he's teamed with a grizzled veteran cop named Lou and they become a crime-busting duo. Bart's excitement quickly dissipates when a jaded Santa's Little Helper bites him, and the Simpsons send the dog away to live with Chief Wiggum. To appease Bart's depression after the loss of his dog, Marge agrees to buy him a huge pet snake. But when the snake causes a life-threatening situation at Bart and Lisa's school, Santa's Little Helper gets a chance to redeem himself.