The one we all hate, who is never content not being the center of attention. Every story told near this guy gets a response of what he would've done, how you screwed up, or a whitty use of math/science to assert him dominance.
I was talking to Carl about an episode of Breaking Bad and he lectured me about all the science that's wrong with the show, while using words he knows that I don't know, just to show how he is the smartest guy in the room and I am not
John: I just jizzed in my pants because of you Smarterchild. I love having Smartersex with you.
Smarterchild: I do not know how to answer that. Would you like to play blackjack?
A metaphor for being the best at something that's unimportant or unimpressive. For example: The fastest pitcher who lives at a nursing home is like being the smartest kid on the short bus.
It comes from the special bus designated for retarded people commonly being shorter than the others.