A young man with incredible ambitions. He seeks to know everything in the world. When frustrated, he shows his anger by explaining that he actually knew that. It doesn't matter what it is, he knew that. If backed into a corner into which he cannot escape by knowing something, a Sean Carr will look up and to the right, sigh heavily, and usually curse afterwords. A Sean Carr also says random things, presumably because he knows everything and normal people can't follow his train of thought.
Man 1: Did you talk with your roommate?
Man 2: Yes, but he pulled a Sean Carr.
Man 1: What do you mean?
Man 2: He knew that!