In 1995, Trent Reznor of Nine Inch Nails started a side-project called "Tapeworm" with live members Danny Lohner and Charlie Clouser, which has been described as a more democratic group as opposed to the Trent led Nine Inch Nails. As time and possible recordings went on, Tool's Maynard James Keenan, Helmet's Page Hamilton, and (at the time) Pantera's Phil Anselmo joined the group and recorded three songs with the group sometime in 1999. Prong's Tommy Victor also recorded with the group.
In 2001, the producer Alan Moulder claimed that Tapeworm has recorded "more than an album's worth of demos". A year later, Charlie left, leaving Trent, Maynard, Danny, and Atticus Ross as members. They booked studio recording time to make an album, but didn't make much progress. At this point John Freese had joined the collaboration.
Supposedly in 2003, an album was ready to be mixed, but legal disputes between Maynard's and Trent's recording labels stopped the album from being released. Finally in 2004, Trent announced that Tapeworm is dead indefinitely, saying Maynard's interest with A Perfect Circle, label issues, and his own growing disinterest as the reasons they broke up.
The first Tapeworm song to surface wasn't even a recording of the song, but a live performance by Maynard's A Perfect Circle. The song, Vacant, was first played in 2001 and was later recorded in the studio and released on eMOTIVe in 2004, albeit named "Passive". In 2009, Maynard's other band Puscifer released "Potions (Divergent Mix)" on "C Is For (Please Insert Sophomoric Genitalia Reference Here)" in 2009. Like APC's version of Vacant, Potions was a cover.
Trent Reznor claims to have no plans to release any Tapeworm recordings, as he says it is not as good as they hoped, and said "the bottom line is this: if the music had been great, all of this probably could have been worked out." Several possible fakes have come up, but even if they're real, there are still plenty of other songs that have yet to see the light of day.