Santa's Little Helper and is the center of the plots of several episodes. During the course of the show, he has fathered litters of puppies, passed obedience school, had surgery for bloat, replaced Duffman as the mascot for Duff Beer, and been trained as a police dog at Springfield's Animal Police Academy. Some of the episodes that focus on Santa's Little Helper have been inspired by popular culture or real experiences that staff members of the show have gone through. Although cartoon animals are often anthropomorphized, Santa's Little Helper generally exhibits canine behavior. Cast member Dan Castellaneta currently provides the dog's sounds on
Good Night (The Simpsons) and looking a little worse for wear." DVD Movie Guide says, "I’ve seen a few additional Ullman shorts and think they’re nearly unwatchable, so I can’t say I miss them, at least not for their entertainment value. However, they’d make a nice historical addition, so it’s too bad we only get this single clip. The first one ever aired, “Good Night Simpsons” runs for 115 unfunny seconds." The Digital Fix says the short extra on the DVD "showcases the superb sense of humour that has made The Simpsons what it is today", and that "the picture quality is quite breathtaking