Robert Zemeckis’ 1985 sci-fi adventure Back to the Future told the story of a hapless teenager named Marty McFly (played by Michael J Fox—who was 24 years old at the time!), who is sent back in time by his eccentric scientist friend “Doc” Brown (played by Christopher Lloyd).

The movie was one of the decade’s most successful, while its 1989 sequel (which throws the action forwards in time, not back) proved even more popular, and ended up the 1980s’ fifth highest-grossing film behind Indiana Jones, Batman, E. T., and Rain Man.

As popular as the Back to the Future franchise is, however, according to screenwriter Bob Gale—who shopped the movie to different producers more than 40 times before it was finally taken on by Universal Studios—in early drafts of the script, the movie was a vastly different story from that which we see on screen today.

Doc Brown’s iconic DeLorean time machine, for instance, was originally a “time chamber,” built from an old refrigerator, which Doc drove around on the back of an old pickup truck. Doc’s pet dog, Einstein, was a pet chimpanzee, until the head of Universal, Sid Sheinberg, laid down the law and uncompromisingly told Gale, “I looked it up: no movie with a chimpanzee ever made any money.”

But of all of the changes the movie went through during pre-production, happily one of them didn’t stick. When Gale and director Robert Zemeckis first approached Sheinberg with the script, he responded with a memo saying he thought it was “terrific,” but that “the title leaves much to be desired.”

Apparently, Sheinberg was worried that including the word “future” in the title of a movie might put people off, and make it appear to be “a cheap, old-fashioned sci-fi flick.” Instead of “Back to the Future,” ultimately, Sheinberg suggested his own title for the film: “Space Man From Pluto.”

Not quite sure what to do with such a questionable change—especially alongside such positive feedback otherwise—Zemeckis decided to approach his mentor at Amblin Entertainment, Steven Spielberg. “We took the memo to Steven,” Gale later recalled, “who told us ‘Don’t worry, I know how to handle him.’”

Spielberg ultimately sent Sheinberg a memo in return, reading “Hi Sid, thanks for your most humorous memo, we all got a big laugh out of it, keep ’em coming.’”

“Steven knew he would too embarrassed to say that he wanted us to take the letter seriously,” Gale explained. “Without Steven, it could have all been very different.”