Following a health scare, Santa's Little Helper is diagnosed as 'chunky' by Adrian, a staff nutritionist and trainer. With Marge Simpson's encouragement, the dog embarks on a rigorous agility training program, transforming from an overweight pet to an agile champion. The clip culminates in Santa's Little Helper triumphantly winning first place in a canine competition, much to the family's delight, as Bart Simpson, voiced by Nancy Cartwright, offers him a celebratory hotdog.