The most noteworthy collaborations between musical superstars fall into two categories: epic (Aerosmith and Run-DMC, Robert Plant and Alison Krauss, Queen and David Bowie) and epically bad (Lou Reed and Metallica, Jimmy Page and P Diddy, Mick Jagger and David Bowie). Between those poles, however, are instances when musical worlds collided to a resounding “eh”. Here are ten collaborations between musical superstars you probably forgot ever happened.

Dave Matthews Band and Alanis Morissette, “Spoon”

“Spoon,” which closes the Dave Matthews Band’s 1998 album Before These Crowded Streets, is written as Jesus’ thoughts as he hung on the cross, phrased in Matthews’ typical dudeishness. (“Wrist to the elbow / Red blood sand / Could Dad be God?”) It contains a banjo interlude and a verse sung by Alanis Morissette, hot off Jagged Little Pill selling a zillion copies. According to Morgan Delancey’s book The Dave Matthews Band: Step Into the Light, Matthews met Morisette the previous year when they both played Neil Young’s annual benefit for The Bridge School and invited her to drop by the studio, resulting in the Canadian banshee singing a bit of Christ’s internal monologue, as imagined by Matthews. That year, she appeared as God Herself in Kevin Smith’s comedy Dogma.

Madonna and Prince, “Love Song”

A duet between Madonna and Prince should have been the biggest song of 1989. However, “Love Song” (whose title is ironic) was never released as a single.  There was plenty of other prime material on Madonna’s Like a Prayer, an album that spawned five top-20 hits. Also, the duet between the two MTV icons was not as amazing as it was in theory. “A potentially fabulous collaboration is wasted on a meandering mid-tempo song that goes nowhere — an exercise in Prince excess,” wrote author J. Randy Taraborrelli in Madonna: An Intimate Biography. Prince composed the song, sang on it and played all the instruments. “Madonna’s role was reduced to sitting in on her own album,” Taraborrelli added. Prince’s guitar work and other touches do pop up more subtly throughout Like a Prayer — so subtly that producer Patrick Leonard can’t remember exactly which tracks feature His Purpleness.