I don't usually buy albums based solely on their album art, but one look at Mammatus' self-titled 2006 effort and I had to heed the piper's call. Featuring artwork by the brilliant Arik Moonhawk Roper, the album lives up to the band's MySpace self-description as “The final war between amps and sea creatures” (note to metalheads: Mammatus seem to have anticipated Metalocalypse's "Dethwater" episode). With churning sludge-riffs, epic fantasy titles, and distant echoed chant-singing, they sound like four Dungeons and Dragons fans who decided to trade their 12-sided dice for down-tuned guitars and combine Yes' 1974 opus "The Gates Of Delirium" with the stoner-rock monolith Holy Mountain by the legendary Sleep. (Religious side-note: Holy Mountain, their record label, is named after the indescribable 1973 Jodorowsky film.)
Mammatus (who take their moniker from a rare and freakish cloud formation) are from the Santa Cruz area and have recorded two albums (the second, The Coast Explodes (2007), is not as heavy as the first, but still good). They are said to be working on a third album, and I hope they come down from their wizards' tower.
Mammatus, "The Righteous Path Through The Forest Of Old":