Brofist

An awesome mix of styles. Really liked this one. The stars and glow around the fist-bump is evocative of Regular Show's supernatural craziness, which is a great start.

The faces are awesome - Mordecai's kinda chill, Rigby's totally into it. Same with the stances, which I don't think could be improved upon. Shading on the hair looks good.

Only thing about it I don't like is that they're shown wearing hoodies, which always happens. And this might just be me being dumb but what's the circle around the top of Rigby's tail supposed to be? It isn't clear to me.

But I'm just nitpicking because this is brilliant overall. It captures the characters' personalities nicely while being different enough from the norm to be interesting.