The moment when Back to the future when Michael J. Fox's Marty McFly disguises himself as "Darth Vader, from the planet Vulcan”, is soundtracked by a song that had already appeared in a film the previous year and starred the actor who was originally cast as Marty. Often heralded as not only one of the best time travel films of all time, but also one of the best film trilogies of all time, Back to the future remains as popular as ever. That being said, it went through a huge process to get to its original form.
Back to the future began production with Eric Stoltz as Marty McFly, but he was dropped weeks into filming after it was determined he was unsuitable for the role. Fortunately, Fox was brought in to fill the void and it was exactly what the 1985 film needed, as well as the two sequels that followed. After reshoots, Back to the future was on the way to what it intended to be, but Stolz's dismissal prevented what would have been an interesting musical recurrence.
Darth Vader's song Back to the Future originally appeared in The Wild Life
The Wild Life, from 1984, had its soundtrack composed by Eddie Van Halen
The music that Marty plays in his father's ears in Back to the future while wearing a hazmat suit was written by Eddie Van Halen, but it was not a genuine Van Halen song. Instead, it appeared as part of the score for 1984 The Wildlife in which Eric Stoltz appeared as Bill Conrad. The song on Marty's cassette tape was part of Eddie Van Halen's soundtrack for The wildlifethat Universal had the rights to use it.
Stolz has appeared in several projects between The wildlife and Back to the futurerelease date, so even though they weren't back-to-back projects for the actor, there would still have been a strong connection between the two films. Lea Thompson, who played Lorraine Baines (Marty's mother) in Back to the futurealso played Anita in The wildlife. Happily, Bill and Anita had a much healthier romantic arc in The wildlife of what Marty ended up enduring with Lorraine.
Why does Marty McFly's tape say "Edward Van Halen" and not "Van Halen"
Eddie's band objected to being credited with writing the track
Van Halen is named after the band's lead singer, Eddie Van Halen. With Marty's Darth Vader moment suggesting that the song on his tape is by the band, it's a little unusual that the name "Edward" is included in lowercase letters before the band's title. The reason behind this, according to the film's DVD commentary, was that while Eddie agreed to have his songwriting credited to himthe band did not authorize the song to be attributed to them - even in Back to the futurefictional scenario.