Robopet
A Robopet is a robotic pet, designed to look like a baby seal, created by Martin Prince and Bart Simpson (although Martin did all the work).
History
Bart needed a project for the science fair when he saw Martin hanging from a tree. Martin agreed to help Bart and Bart came up with an idea for a robotic pet (after seeing Santa's Little Helper with a Darth Vader mask on). Together, they made the robot, in the design of a baby seal as everyone goes "awwwww" when they see them. After turning it on for the first time, it tried to attack Bart, and Martin changes a wire around inside it and it becomes nice.
After taking it to the science fair, they win first prize, beating Lisa's scientific discovery that a meteor would strike Springfield years in the future, wiping them out. much to Lisa's annoyance.
Bart then takes the Robopet to the Springfield Retirement Castle when it is an instant hit with Jasper Beardley, making him a lot happier. Bart then mass produces them and all the residents have them. However, funeral directors dislike that less old people are dying because they are happier and reprogram them to make them kill the old people, one of them killing Alice Glick.
Bart and Martin go to Professor Frink to ask him to reprogram them again from their prison cell. He enlists the help of Benjamin, Doug and Gary. Together, they reprogram them and make them escape from prison and back to the Retirement Castle.