How many professional soccer teams do the Harlem Shake? Well, the Seattle Sounders do. Check out this video of the team doing the dance at a preseason "meeting". See if you can pick out Sigi in the group. Actually, not too sure Sigi took part, but Eddie Johnson is over to the left.
This video was released from the official Sounders team YouTube channel. So, yeah, it wasn't something the team or certain players did on their own but the Sounders. Got to love that.