Warning: Spoilers ahead for tonight's episode of The Big Bang Theory.
The Big Bang Theory has become known, in its 10 seasons on the air, for enlisting the help of several guest stars to enhance the stories the show tells of the group of funny friends we've all come to know and love. It was announced a few weeks ago that tonight's episode, titled "The Property Division Collision," would feature a guest appearance from iconic actor Christopher Lloyd, but we didn't know who he'd be playing or how his character would feature into the main plot. Episode 10 of The Big Bang Theory saw Christopher Lloyd playing Theodore, Penny and Leonard's new oddball roommate. Let me back up and explain a bit.
Since Amy and Sheldon seem to be happily cohabitating over in Penny's apartment while she finally gets to live with Leonard, Amy suggested at the beginning of the episode that the two of them redecorate her apartment to make it more suitable for their tastes. This led to Sheldon realizing that he misses pretty much everything from the home he shared with Leonard for the past 13 years, like the Game of Thrones Longclaw sword and their one of a kind Mr. Spock cuckoo clock.
After Leonard realizes that Sheldon is going to find a way to justify taking all of their shared possessions over to Penny's, he gives in and says he only wants one thing: their official apartment flag. Of course, Sheldon really wants this, too. Especially since he designed the gold and pale blue item. And, well, you know how Sheldon feels about flags he didn't design, so you can imagine how attached he is to this one.
When Sheldon finds Leonard in the laundry room wearing the flag like a toga, and without underwear, he decides to play even dirtier and get back at Leonard by renting out his room at the apartment. This means that Penny and Leonard come home one day to find Theodore standing in their kitchen making a sandwich. In true Christopher Lloyd--who is possibly best known for portraying Doc Brown in the Back to the Future films--fashion, Theodore is more than a little odd. He, apparently, could produce no form of ID for Sheldon and claims that he excels at rubbing his junk on stuff. So, you know, he's exactly the kind of person you want to share an apartment with.
Theodore does come in handy, though. He hears an argument between the friends and tells Sheldon and Leonard that they're fighting "because of love." Obviously, Theodore explains, the two really care about each other and are having trouble coming to terms with the new nature of their friendship. This, of course, gets them to make peace. So, it looks like Christopher Lloyd's slightly nutty character actually helped Sheldon in more ways than one.
You can catch up on The Big Bang Theory Thursdays on CBS.