Someone who doesn't talk much. People usually tend to not even notice them when in a conversation with multiple people. These socially challenged ones don't say a word, but when they do, they're fricking hilarious!
Dude 1: So I was waiting for the bus and all of a sudden a bird swoops down and into my hair.
Dude 2: lol, did it get stuck?
Dude 1: No, it attacked my hair then flew off.
Socially challenged person:...
Dude 1: So, did anything interesting happen to you?
Dude 2: Nah, just the usual.
Socially challenged person: PUDDING!
Dudes 1 and 2: OMFG WHERE DID U COME FROM?!
Socially challenged person: I was here the whole time.
Dudes 1 and 2: HAHA, well whatever you said was frickin' hilarious!