 " Exit Through the <unk> @-@ E @-@ Mart " is the fifteenth episode of the twenty @-@ third season of the American animated television sitcom The Simpsons . It originally aired on the Fox network in the United States on March 4 , 2012 . In the episode , Bart is punished by Homer after causing trouble . He gets revenge on his father by <unk> @-@ painting images of him with the word " <unk> " all over Springfield . Street artist Shepard <unk> encounters Bart one night and offers him a gallery show of Bart 's artworks . However , Chief <unk> suddenly appears during the show and arrests Bart for covering the town in graffiti . It turns out that <unk> is an undercover officer working for <unk> . 
