Seriously, wth is it really? The thing is freaking huge! ..and he's not even flexing. It is literally the first thing I see every time Tmac shoots a free throw and I can't help but stare at it. Someone explain
It's called a cephalic vein. Of variable size, location, and superficiality in most ppl. Of course being ripped helps.
Yeah that's like his defining feature lol. I always notice it when he's shooting free throws too. I noticed it slightly visible on my left arm too the other day after doing some pull-ups.