THE MOST BRUTAL SONG EVER

How about Hammer Smashed Face by CC or Deranged Epidemic by Disgorge. Or one of the greatest songs ever created, Spheres of Madness by Decapited. Those are pretty brutal.
 
Iron Monkey - Big Loader (or Web of Piss). Put on headphones, place on "very loud" and keep on a loop. Now drink beer until your vision fails.

Heavy.