"Until It Sleeps" is a song by American heavy metal band Metallica, released on May 20, 1996, as the lead single from their 1996 album, Load. It was the band's first number one song on the US BillboardHot Mainstream Rock Tracks chart, as well as their first and only song as of the release of Hardwired... to Self-Destruct to hit the top 10 of the Billboard Hot 100, debuting and peaking at number 10. Outside the US, the song topped the charts of Australia, Denmark, Finland, Hungary, and Sweden. Moby produced a remix of the song, titled "Until It Sleeps (Herman Melville Mix)".
The song was performed with orchestral accompaniment on the album S&M. An early demo version of this song was entitled "F.O.B.D." (recorded on December 8, 1995) because it reminded the band members of the Soundgarden song "Fell on Black Days", in that the "It grips you...It stains you..." refrain is in the same 6/4 time signature that "Fell on Black Days" is in. The band can be heard saying "Fell on Black Days" on the fanclub-only Fancan 1 CD just prior to jamming on a portion of "Until It Sleeps". The 10-inch vinyl version of the single is red in color. Moby, credited as "Herman Melville", did an industrial-sounding remix used as a B-side.
"Until It Sleeps" became the first "officially" pirated MP3 when it was released by Compress 'Da Audio (a piracy group and spinoff of the Warez scene) via an Internet Relay Chat network on August 10, 1996. An EFnet member on the #mpeg3 IRC channel named Coyote666 was responsible for creating the first mp3 ripping software.
The lyrics of the song, written by Hetfield, address his mother's battle with cancer, to which the "it" in the title refers. They can be seen as either describing the emotional pain he feels for the loss, or the physical pain his mother was feeling while she was ill. Both of his parents were Christian Scientists, and did not believe in medicine. The lyrics are also interpreted as dealing with anger issues. Hetfield's father, Virgil, died in late 1996, during Metallica's Load tour.