That depends on what you mean by brutal. Musically, I could list tons. However, I feel something else should be mentioned. This one band, whose name escapes me at the moment, found their singer, dead. He had been shot in the head (I'm pretty sure it was a suicide). They took a picture of it and used it for an album's cover art (it wasn't a studio album, it was an EP, compilation, or live album). I think that kinda trumps every other band I know in terms of brutality.
idk ha or whitechapel
Gwar has horrible music though..
but tnx for your comment