Poser

One who changes their personailty, attitude, and looks based on an influence. The person can also be considered fake. If a sport is involved, a poser may pretend to be good at it. If a clique is involved, the poser may adapt the steriotype style of the clique. Posers are widely disliked throughout... everywhere.

Chris: Dude that fatass Mike can't seriously skate, why does he even try?
Sean: Dude, because he's the biggest poser I know