Very specific band name. Not approximately a couple of hundred, not 199, not 201, exactly 200 stab wounds.
Which seems like an attempt to cover up the death by virtue of looking like overkill (though they sure don't sound like Overkill) while actually being a highly organized and disciplined stabber.
I mean, to keep track of how many stabs you're doing all the way to 200, and not get carried away and just keep going? That's discipline! Or, maybe they got carried away at 100, did the 101st, got mad at themselves for the lack of discipline and had to go to 200 to prove that they could stop while also having a compulsion to work in groups of 100.
That raises the question of why not 300? Is it because it's an odd number, or just too much work? Obviously, 400 is just right out, who could stab that many times? The arm would be exhausted. I guess you could build a stabbing machine, but at that point, where's the fun?