Temp Check

Synopsis
Rigby hires a temp (temporary worker), Doug the river otter, to do his work for him. However, Doug befriends Mordecai, and Rigby is jealous when Mordecai begins to hang out with Doug more than Rigby. Worse, Rigby learns Doug's secret: that he is a shapeshifting criminal, who plans to turn himself into a clone of Rigby in order to impersonate and replace him.

Plot
The episode starts with Mordecai and Rigby just finishing mowing the lawn at an ultimate frisbee field. They jokingly pretend to give a celebratory hug, but both back away at the last second, claiming it's "sick." Just then, Benson arrives, saying that it needs another inch cut off, because the ultimate frisbee players will trip and sue them. Rigby thinks that's lame, and Benson threatens to fire Rigby. Rigby complains, and Mordecai says that he can't just hire someone to do all of his work for him.

Rigby realizes he could do just that, and the scene moves to that park's entering gate. Rigby is seen using a blue marker to decorating a stand. Moredcai comes, asking why Rigby bailed on him from the football field. Rigby says that he's going to hire a temp. Rigby talks to a fat guy on fire, a pirate, and a muscular redneck, but each is weird and stupid. Just when Rigby is about to give up, a bus arrives and out comes a river otter by the name of Doug, who coincidentally, who is desperately looking for a job. He's qualified - he even notices that the grass is an inch too tall - so Rigby hires him. Mordecai and Doug are raking leaves, and Rigby hands out an envelope to Doug containing his paycheck, but snatches it back and just hands him the coins. Doug still happily accepts this small amount, saying it's the most he's ever been paid.

Doug continues to be overly appreciative of the meager accommodations, and Mordecai begins taking a liking to him. His Rigby impression is dead-on. Mordecai and Doug take on Muscle Man and High-Five Ghost in two-on-two basketball, have fun working the snack bar, and do park chores, all while Doug more and more resembles Rigby, with his hair, lack of clothes, tail, and eyes. Benson even calls Doug "Rigby" when congratulating the two on good work.

As Rigby confronts Mordecai about Doug's behavior, he discovers that even Mordecai couldn't tell the two apart. As Rigby confronts Doug just leaving the shower, he tries to fire his "temp," at which point Doug refuses: "I'm more Rigby than you were... or will be!" He then morphs into a form identical to Rigby's. They wrestle and go downstairs, at which point Mordecai sees the identical duo and realizes the problem. Even Skips can't tell who's who. Benson runs the two through a series of tests: they punch Mordecai (weakly), they play video games (poorly), they mop the floor (and give up), and answer Rigby-related questions correctly. As one Rigby correctly identifies Rigby's greatest fear as "amusement park mascots," Mordecai gives that Rigby a celebratory hug, and the other Rigby whines and sulks away. That allows Mordecai to identify the real Rigby, as only the real one could whine that much, and the real Rigby would never hug him. He is caught, and the police arrest him. Doug's full name is revealed as "Doug 'The Doppleganger' Sheblowski" and the crew is informed that he's been pulling this scam across the country.

Doug in his true, much deeper voice is walked up to Rigby, and lets him know that while Doug has little to be thankful for, Rigby has plenty: friends, a job, a warm bed. Rigby dismisses him as a windbag, and Benson calls this "unbelievable." As Benson is the only one who hires and fires, Rigby is threatened with the latter if he doesn't perform toilet duty for the next three months. The show closes with Rigby offering Mordecai a way to get "an easy ten bucks."