Dokaka

I'll just get this out in the open right now, I think Dokaka is insane. In a very good way. If you've played "We Love Katamari", then you are very familliar with his style, as he did the a capella version of the main theme. And it's incredible. Strictly speaking, he's a beat-boxer, but like none that you have ever heard before. He doesn't really do the whole "beat" thing so much as make all kinds of crazy noise with his mouth. Usually rather high pitched noise. Fast high pitched noise. He's very experimental and influenced by various heavy metal groups like Iron Maiden, Slayer and Black Sabbath instead of a bunch of hip-hop. He also did some work with Bjork on her Vespertine album along with the likes of Mike Patton and Rahzel. You can hear a ton of his work on his site, and there are more than a few super crazy videos (make sure to watch that one all the way to the end) out there too.