Cream's psych rock grew out of the mid-'60s collision of American blues and the British Invasion. In addition to Robert Johnson's deft picking and demonic boogie (“32-20 Blues”), their chops utilise The Paul Butterfield Blues Band's Chicago toughness and heady jamming (“Blues with a Feeling”), all of which come slathered in overdriven fuzz like that heard in The Pretty Things' snarling freakbeat raver “Buzz the Jerk”.