"Donnie Fatso" is the ninth episode in the twenty-second season of the American animated television series The Simpsons. It first aired on the Fox network in the United States on December 12, 2010. The plot revolves around an FBI agent, who helps Homer go undercover to infiltrate Fat Tony's mob. Homer agrees to this in hopes of decreasing his sentence after being charged for bribery. This episode is a reference to Goodfellas as well as real-life FBI agent Donnie Brasco.