It's Always Sunny In Philadelphia: 10 Best Characters Who Appeared After Season One

Hands down the best celebrity guest performance in the show's entirety.

Sean William Scott will always be Stifler to a generation of viewers, but here, he brings an effortlessly cool charm to a great character. On Mac Day, an episode in season nine where for twenty four hours the gang have to do whatever Mac wants, his cousin arrives.

Known only as Country Mac, SWS knocks it out of the park as he embodies everything that Mac wishes he was. Quick witted and funny, Country Mac has the gang laughing on command. Wanting to fake an extreme stunt for Project Badass, Mac refuses to actually jump off a massive bridge. Country Mac does it without issue.

With the gang wanting to replace Mac with his country based cousin, the final nail in Mac's coffin is when they are violently confronted outside of a karate tournament. As Mac literally soils himself, Country Mac disarms their attackers, complete with a badass line. For once, the ocular pat-down was used to brilliant effect.

With the gang in awe, Country Mac drives off slowly, falls off his bike and smashes his head against the ground, killing himself. It's a hysterical ending to an episode, as is Mac's ridiculous karate display at the memorial service.

R.I.P Country Mac.