These days you hear that sludgy, crypto-psychedelic heavy metal called "stoner rock" all over the place — or at least the influence of such when so many bands rediscover early metal influences like Deep Purple and UFO. Sleep didn't necessarily pioneer stoner rock or doom metal, but its 1992 album, Sleep's Holy Mountain, is the Rosetta Stone when it comes to understanding the aesthetic of virtually everything that has come since. When Sleep first came around, most metal tried to go glam, play faster or aim only for sheer brutality. The band varied the density and intensity of its riffs and dynamics to create an elemental, oddly hypnotic sense of disorientation. Now touring with a performance of Holy Mountain in its entirety, Sleep will show us how doom is really done.