This is a new up and coming hip hop group. Right now it's a bit in the obscure age, but goddamn is this some crazy shit.
First mixtape called "Exmilitary" is free: http://thirdworlds.net/files/Death Grips - Exmilitary.zip
Get it if you dare.
They have a few music videos too.
Bit mental really.
It's not for the faint-hearted because this can make you feel a bit out of sorts. The guy screams into the microphone and then music is then forced around it in this ridiculous way. Some great samples here, especially how it starts with a Charles Manson interview.