You should likely be more specific with what you'd like to accomplish here. "What should I do in X situation?" is likely to be closed.

I don't know where you are, but here in the USA he's way past the line of a criminal matter, although your conduct certainly didn't help.

Regardless of where you are "legality" matters little unless you (or someone) is willing to follow up on this using the correct channels and a lot of effort. It would be reasonable, however, to request to never have to work with that particular person again.

'Russia' has been added by OP, after some research, I think that your colleague might suffer from PTSD (PostTraumaticStressDisorder). I found out that military training could be so hard and focused on mean and violent behavior (ie Spetsnaz) that it could lead to such sad ending. One approach would be asking your HR/manager if your colleague could suffer from such a training and if it could explain part of his behavior. Yes, this kind of behavior is unacceptable. I might be wrong, but just want to figure out why it happened, understanding and help are far better than fighting back anyway...

If you still have the scratches on your neck, it could be a good idea to let a doctor see them, to have a medical evidence of injuries, even if they are small. Basically in case this issue escalates badly and you end in a court. Also, document everything.

So you insulted him, then dared him to beat you, then he stopped when you asked. Hmm. Do you not think that maybe part of the problem here was you?

@Lightness Races in Orbit You are not quite right here. It was Bob who verbally insulted me first. Anyway it doesn't change the case much. Though I agree that "Dare you!" wasn't the best reply in these circumstances.

@LightnessRacesinOrbit are you condoning physical assault?

@Nobilis: I would not condone unsolicited physical assault, but if you say "come at me" and someone then comes at you for precisely as long as you asked them to, I don't know what else you expect. Next you'll be accusing children who play fight of being out of control psychopaths.

In any other country in the world, there certainly was enough harm to warrant calling the police. Is there something special about Russia that makes it different there?

@LightnessRacesinOrbit There is still a lot of difference in A:**What are you going to do, beat me?** B:**If you ask for it!* compared to what I understood was the situation B:"Stop bugging me with your strange pronunciation opinion, or I am going to beat it out of you." A (aware there are witnesses and sure B would not go for it):**Dare you! Beating me, really?** In the first case, there is some provocative action by A that could be seen as the first "aggression". In the second case, it is definitely B escalating a discussion to a physical fight.

When you escalate, it's likely you both get fired, for the insult race ended up with fight. It is not kindergarten, it doesn't matter who hit first if both parties were eagerly seeking fist fight.

@LightnessRacesinOrbit Bullshit. Nothing legitimizes physical assault. The aggressor could have simply stopped responding to OP and the discussion would have ended. With your point of view, everywhere should be a jungle and whomever more aggressive should be right.

@skymningen: I'm employing hyperbole a little, I'll admit, as it seems like the OP's actual intention was not to literally solicit a physical altercation. Note that my original comment merely suggests that the OP is "part of the problem", which they agreed with. It's Nobilis who started taking the conversation to extremes for some reason.

@LightnessRacesinOrbit Wrestlers, boxers are not terrible people. That's because that is their job. OTOH, software development does not involve jumping on someone when you have a disagreement.

@Utku: It doesn't involve eating, breathing, having a bath either but these are still things that happen. This question is not about software development. It is about a disagreement between two parties and the fact that both were acting unprofessionally. Period.

I saw one mention of PTSD above and was surprised there was just one. While it's no excuse or reason for the behavior, this guy might need some help. Although the colleague who attacked me has been slightly aggressive lately, it was very strange for him to act like that. Go have a beer with the guy.

Maybe be that kind of behavior is ok in Russia or where ever you are, but if you worked in the states, you'd both be fired for cause outright. Do not pass Go, Do not collect $200, we'll box up your personal belongings and ship them to you.

@LightnessRacesinOrbit Nothing excuses physical assault, you blaming it on the person who was attacked implies that there is a situation in which such a response is acceptable.