Sheldon gets into an argument with Stephen Hawking over a game of Words With Friends on The Big Bang Theory. "The Extract Obliteration" is the sixth episode of the show's sixth season.
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The Big Bang Theory Season 6 Episode 6 Quotes

What do Sheldon Cooper and the black hole have in common? They both suck.

Professor Hawking

Oh, it's only a matter of time before we're coming up with fun nicknames for each other. I'll be Coop. He'll be Wheels. If he's okay with that.

Sheldon