A person, specifically an Asian person, who is too boss at doing anything, especially math. Shy at first, but get to know him and he'll blow your brains out from his epicness.
Dude, did you hear about that Asion boy, Daniel? He won 1st place in some math contest. He's such a megabeast.
Similiar to megabank, megabank beast guap is an insanely, disgustingly awesome achievement. To be megabank beast guap someone or something must rule complete and total ass. He, she, or it must be so fucking great that there is no word in any language on this fucking planet that can describe them.