Mystic Fire is a 2002 album by Mountain. It features the song "Immortal", which was cowritten with and originally performed by Clutch.
The song "Immortal" was originally released with different lyrics, and a different arrangement, as the song "Baby I'm Down" on Mountain (1969), Leslie West's first solo album. Clutch covered the song on their 2001 album Pure Rock Fury, rearranging it and changing the lyrics; their version features a guitar solo from Leslie West. Mountain then covered that version of the song on this album.