Rigby finds an old tape with one of his former favorite songs on it, only to find that it's not as good as he remembers. Problem is, the song gets lodged in his brain and cannot stop humming or singing it so Mordecai tries various methods to get rid of it.
Season 2 Episode 13 of Regular Show resulted in a 0.00 rating in the 18-49 demographic.
Two groundskeepers, Mordecai (a six-foot-tall blue jay) and Rigby (a hyperactive raccoon) are best friends who spend their days trying to entertain themselves by any means necessary, much to the displeasure of Benson (their boss, who is a gumball machine) and to the delight of Pops (an older, lollipop-headed gentleman).
Their everyday pursuits often lead to things spiraling out of control and into the surreal: they open portals to other dimensions, summon demons via an -80s arcade game and accidentally use choreographed dance moves to send co-workers to the moon.