When the ratings for "Itchy and Scratchy" are dropping, Roger Meyers, Jr. gets a suggestion from Lisa that they should rejuvenate the show with the addition of a new character. They follow the animal enemy chain by going "mouse-cat-dog", and then a new character, Poochie is born. Lisa remarks that new characters are just a desperate effort to boost shows with low ratings, and at this point a character named Roy walks into the living room. It's suggested he has been living with the Simpsons for some time.
Still, at the encouragement of the rest of his family, Homer auditions for the voice of Poochie, and he gets the job. Homer then meets June Bellamy, who does the voices for Itchy and Scratchy. He makes friends with her when he fires back at nerds and engrossed fans at a comic book convention.
When his debut cartoon premieres, it gets the worst reviews ever. For once this is not Homer's fault, but due to poor writing Poochie prevented the violence that the viewers love, causing everyone to hate Poochie. He overhears the staff saying they should kill him off.
When Roger Meyers, Jr. says that Homer is too much trouble and he could be laid off, June Bellamy comes to his defense by putting her foot down. At the next episode's recording, Homer reads lines that he wrote himself about how no-one likes him (Poochie) initially, but they should give him another chance. By the time the episode airs, the company have amateurishly substituted Homers speech with new dialogue, saying Poochie has returned to his home planet and died along the way. Everyone is excited about Poochie dying except for Homer. He soon gets over his disappointment, Roy declares he is moving out, Itchy and Scratchy go back to their basics and their ratings are better than ever.
The addition of Roy is a reference to a suggestion made by Fox executives that the writers add a new character to the show to live with the Simpsons and "liven up the show". The staff rejected the idea and inserted Roy, without explanation, as a joke. Roy was previously planned to appear in one of the alternate universes of "Time and Punishment".
The original plan for Poochie was that he would be incredibly rich and would enslave Itchy and Scratchy in his gold mine. Itchy and Scratchy would plan to kill Poochie, but fail and die themselves.
Steven Dean Moore's cel with the episode number was lifted up after Poochie (dubbed by Roger Myers) said, "I have to go now. My planet needs me," according to the audio commentary. He told them how to the lift the cel up.
Krusty the Clown Show Characters, Locations and Key Episodes