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
The Simpsons their original format. In July 2017, all episodes were made available for purchase on the iTunes Store, in the United States. The popularity of "The Simpsons" has made it a billion-dollar merchandising industry. The title family and supporting characters appear on everything from T-shirts to posters. "The Simpsons" has been used as a theme for special editions of well-known board games, including Clue, Scrabble, Monopoly, Operation, and The Game of Life, as well as the trivia games What Would Homer Do? and Simpsons "Jeopardy!". Several card games such as trump cards and The Simpsons Trading Card Game have also been