Watch: Jack Black Performs Insane "War Pigs" Cover With Black Sabbath's Geezer Butler at Tom Morello's Fest

When comedian Jack Black and his Black Sabbath tribute band took the stage on Saturday night, they brought out a heavy hitter to assist with the heavy jams. Geezer Butler […] The post Watch: Jack Black Performs Insane "War Pigs" Cover With Black Sabbath's Geezer Butler at Tom…