Santa's Little Helper the dog was a "sympathetic" character. Welker has been praised by staff members for his performances on the show. David Mirkin has noted that "he can do anything, and it fits perfectly. You forget you're listening to a guy, and he's a pleasure to work with." Groening has commented that he was "unbelievably good" at doing animal noises. After 1995, Castellaneta voiced Santa's Little Helper on his own while Welker performed other animal noises until his full departure in 2002, when he was denied a pay raise. In the "questions and answers" section on his website, Welker revealed that the
Bart's Dog Gets an "F" shorts, the characters spun off into their own half-hour prime-time show on the Fox network named "The Simpsons". Matt Groening, the series' creator, wanted Ullman to make a guest appearance in one of the shorts, but was told that she was too busy with the rest of "The Tracey Ullman Show". When her show was canceled in 1990, Ullman agreed to do a guest appearance on "The Simpsons" after being asked by Groening once again. The animal noises for the episode, including those by Santa's Little Helper, were performed by Frank Welker. It was the first "The Simpsons" episode Welker