You are in the club with your girlfriend, this guy come over an slaps ass of your gf.
What are you gonna do?
I have taken down bigger dudes than this, its not a big thing you just have to be fast and make your mind up before it all goes down, most people loose a brawl because their mind isn't set, they worry about consequence (what if I hit him too hard and he dies?) and other things.
You loose if you do that.
Oh an I hate to break this to you all, muscle means fuck all in a brawl.