Yep. Been knocked out twice. Both in my early twenties, before i'd learned that it was better to be judged by 12 than carried by 6. Alcohol and peacemaking don't mix.
Now obviously i'm still alive lol, but i could have easily been dead. the last instance was of me being sucker punched dead in the mouth at 23 outside a bar. And literally i only vaguely remember the dudes fist flying towards my face, then NOTHING. BLANK.
Then i remember waking up, what i assume was sometime later, and staggering on my feet and muttering for help lol. Then it went to black again. Then the next thing i remember i was waking up with my buddy and whoever else looking over me, asking me if i was alright. Then i next remember being in the Emergency Room.
My takeaway was: Being sucker punched and knocked the fuck out doesn't feel good, lol. It doesn't particularly hurt, mind you, at least until you have to see the dentist, but it's clearly damaging as i don't remember 75-90% of the shot that preceded and followed the event (brain damage). It's not something i'd ever want to go through again. And mind you, i've done plenty of training and sparring in boxing since my early mid-20's, so i wasn't and am not a neophyte or easy mark. But in the streets, neither one of those two things guarantees that you won't be the victim of a one shot hitter-quitter.
And fwiw (the post mortem) : My chins never been the same since. Thankfully i've got some degree of training, skill, and the common sense to not get into drunken altercations. And i suppose being 40 years old is part of that, but if i ever got touched with a solid punch to the chin/jaw again, i'd fold like a cheap fucking lawn chair.. Chuck Liddell/RJJ/David Price.