This video starts out pretty standard, by Russian dash cam norms. One guy says one thing, another guy says another thing, and before you know it you have an all-out brawl. One of the guys looks especially unhinged, until you realize it's just his entire arm that's become unhinged.
In fairness, it looks like the dude with the arm flapping lazily in the breeze was pretty much the instigator of the whole thing, along with the driver of the vehicle he was in.
I'm not one to encourage violence in any way, shape, or form, but when a one-armed bandit tries to tear you out of your seat, headbutt you in the face, and then he and another guy gang up on your friend to do the same, well, you know.
Sometimes you just have to literally tear a guy's arm off.