The Simpsons season 24 episode 8
Episode title: To Cur, with Love
Grampa has to move into the Simpsons house following a fire at the retirement home, and on moving day, Homer 'throws his back out' and 'rests' at home. He later finds an advert for a video game, Villageville on his myPad, and starts playing. During that time, Homer loses Santa's Little Helper. When the family find him, Homer doesn't seem to care because he's "not a dog person". Grampa later tells the rest of the family the story of Homer's childhood companion, pet dog Bongo.