At the time of the recording of The Apocalypse Now Sessions, the band also included Grateful Dead bassist Phil Lesh, along with percussionists Airto Moreira, Greg Errico, Jim Loveless, and Jordan Amarantha, guitarist Mike Hinton, and vocalist Flora Purim.

After attending a Grateful Dead concert, director Francis Ford Coppola asked Mickey Hart and Bill Kreutzmann to record drum music for his film Apocalypse Now, much of which takes place along a river in the jungle during the Vietnam War.

After the recording of The Apocalypse Now Sessions, The Beast was incorporated into the "Drums" section of Grateful Dead concerts, an extended percussion duet performed by Hart and Kreutzmann in the middle of the second set of songs.

[4][6] Allmusic said, "Three members of The Grateful Dead (Mickey Hart, Bill Kreutzmann, and Phil Lesh) improvise on percussion instruments with several other musicians to provide incidental music for the movie Apocalypse Now.

"[7] Smithsonian Folkways, writing about the CD, said, "Director Francis Ford Coppola asked Mickey Hart to provide a percussive underscore for his 1979 film Apocalypse Now.