Breakaway Pop Hit: The soundtracks to his movies are much better remembered than the movies themselves.
Hey, It's That Girl!: Pearl, one of Prince's dancers from the "Diamonds And Pearls" tour and videos, is better known by her real name, Robia LaMorte, who played Jenny Calendar.
Keep Circulating the Tapes: The Black Album was pulled just weeks before its intended release and was replaced by Lovesexy, causing it to become one of the most bootlegged albums of all time. (Such was the scale of its bootlegging, a contemporary Rolling Stone interview saw The Edge cite it as his favourite album of the year, despite not being officially released.) The album garnered a limited official release in 1994, in an attempt to help close off his contract with Warner Bros. (It didn't work.) Some of his unreleased stuff tends to leak out once in a while on bootlegs, and several others were released on the Internet through the NPG Music Club. Good luck catching them all.
Money, Dear Boy: Why the Black Album finally saw release. Prince also used this moment to unsuccessfully get out of his contract with Warner Bros.
Talking to Himself: Prince distorts his voice electronically to have a dialogue between himself and God in "Temptation". He also sped up his voice on several occasions; many excursions into the upper range were intended to sound like a female alter ego named Camille.
Some production accidents even found their way into the completed songs. For instance, engineer Susan Rogers accidentally caused some words to be distorted while recording the vocals to "If I Was Your Girlfriend" through a technical error, and recounted to Alex Hahn that she thought Prince "was going to rip my head off!". Upon listening, Prince loved the effect and kept it in.
Similarly, "The Ballad of Dorothy Parker" quite noticeably lacks low-end and sounds somewhat thin and muddy. This was also the result of a technical error at his Chanhassen home studio. The Prince Vault has the details, but for TLDR: Prince was recording through a console with two separate power supplies, and did not test it beforehand. During the "Dorothy Parker" session, the house was affected by a power cut, and lost one of the power supplies. Susan Rogers noticed that the music sounded flat, but she didn't want to interrupt recording to point it out, and only discovered the problem after the song had been finished. Prince liked the recording, and did not attempt to re-do the song with the fixed console.
Vaporware: Prince being Prince, you can expect a metric ton of this, which are chronicled in detail here. Some of the more notables ones are Roadhouse Garden, announced as a return of The Revolution before he even asked the other members to rejoin; and A Celebration, a re-recorded greatest hits that was quashed by Warner Bros. releasing The Very Best of Prince. Many were announced in press conferences or in tourbooks.
"Computer Blue" was originally a 14-minute suite with different parts, additional lyrics, solos, a passage known by fans as the "Hallway Speech", and ending with three full minutes of screechy guitar feedback. It was planned to be included in its complete form on Purple Rain. However, "Take Me With U" was added to the album's tracklist. In order to fit into the album's running time, "Computer Blue" was hacked down to 4 minutes. The result was great because Prince had the good sense to pull an Adaptation Distillation and only keep the best parts of the song. One of the parts of the original, a synth solo, was included in the film during a rehearsal scene, and the drastically abridged feedback outro was used to transition into "Darling Nikki". The entire original thing tends to show up on bootlegs every once in a while, with varying sound quality.
Michael Jackson's "Bad" was originally conceived as a duet with him. Prince declined, saying the song was good enough without him. He was right, but still...
Sign "☮" the Times was initially planned to be a Revolution-featuring album titled Dream Factory. When Wendy & Lisa decided they were done with Prince, he shelved the project, instead focusing on an album of sped-up, female-sounding vocals for an album titled (and credited to) Camille. Both projects got mushed together into a triple album named Crystal Ball, which Prince actually wanted to release, also under the name Camille. He eventually had to cut it down to what we hear today. Emancipation kind of proved that the Warner Bros. had a point in nixing the idea.
The Love Symbol Album was meant to be a Concept Album with a story told in seguesnote The first segue mentions a terrible recession in... 1997. Off by only ten years, or a creepily accurate prediction of that year's Asian financial crisis?, but Prince had to chuck out most of the segues due to space constraints to fit the whole album on a CD after deciding to add the song "I Wanna Melt With U"note the final, 18-song CD stands at 74:58, so the 24-song configuration with all the segues would have clearly pushed it past a CD's 78 minute limit, and only two survived (the ones featuring Kirstie Alley), leaving behind something really confusing.
In addition, Miles Davis' album Tutu was originally going to be made in collaboration with Prince, but this role ultimately went to Marcus Miller. The closing track "Full Nelson" liberally borrows from Prince's late-80s playbook and really offers a glimpse as to what could've happened there. Prince did try to donate a song, "Can I Play With U?", but pulled it out because he felt it didn't fit with the sound of the album.