I should've said one shotting an opponent in a chaotic fist fight is a rare occurrence.

I mean, getting knocked out is pretty serious. It's brain damage no matter which way you look at it. It's why I always get paranoid about people trying to act tough by sticking their head up / towards someone. It's arguably the dumbest thing you can do and arguably the reason why people think it's a good idea is because they've probably seen it in a movie, but the penalty of failure is that you might not remember your name in the morning.. Punching isn't even the most effective knock-out technique since, as I've experienced, your cheekbones and bones will crack / fracture / break to absorb the impact. Open hand slapping is more effective.

I don't think movies even portray knock-outs correctly... it affects you for weeks / months after the event. Although, I've never been knocked out, but it's happened to friends where they developed slurred speech.

It's also missing the other factors that are going on when you're taking / giving punches. You're causing internal bleeding, not just bruising and swelling. If you've ever been punched and felt a water sensation running down the inside of your skin; that's internal bleeding.

I would never willingly let someone punch my head. I can't empathise with the MMA fighter in the video for that reason because I think it's unreasonable to assume that the other party is okay with what he did... even if he is a fraud.