Not sure if it's a bonafide heckler story, but we played a gig in a real classy joint once. It was a mile or two from a college campus and they had $2.50 pitchers of PBR. Between the second and third set, the singer and his GF went outside on break. When they were walking back in, some drunk football player type says something inappropriate about the singers girlfriend.
I was onstage all ready to start the third set and kinda caught what was going on, but really thought nothing of it.
So, they exchanged a few words, and the singer turns my way to head back up to the stage. At this point, the genius says something like "Yeah, I thought so, you're just a little *****." Now, the exchange they had previously included lots and lots of profanity, but for some reason, this was the word that started it all. The singer turns back towards the guy and says "I'm a *****? You're a *****."
And it was on. Big drunken dude gets up, lets loose a war whoop and charges the singer with his head down and his arms spread wide. My singer doesn't ever drink, and his reaction time was better than the drunk dude. He kinda pivoted like a bullfighter, grabbed the guy around the neck as he came by, and ran him headfirst into a support post that was to the outside of some tables.
Then he walked up onstage and we started the third set.
It was FREAKY!! I expected that guy and his buddies to be outside waiting for us when the night was through. No one was waiting when we got outside though, so I expect he may have been in the emergency room.