The beginning of Samurai X: Trust when Hiko (being the badass that he always is, of course) is all like:
"You won't be alive long enough to remember my name." Then that idiot runs up to him and he just mutillates him with three strokes of the blade. Ah, so awesome.
It wasn't really nasty, but I guess some people might think so. I thought it was awesome. I totally jumped out of my seat and screamed in joy the first time I saw it. So cool.