15 things you probably didn't know about 'Back to the Future'

It's been 30 years, but Back to the Future is still blowing our minds with some serious (expletive).

We've probably seen the movie a thousand times, but there are tons of things even we didn't know about the 1985 sci-fi classic. So on Future Day, to welcome Marty McFly to the 21st century, here are some totally heavy fun facts about the Back to the Future franchise for you.

1. Eric Stoltz actually made it into the final movie

Eric Stoltz was famously hired then fired a few weeks into playing Marty McFly -- this is probably the one piece of trivia you already know. You'd be hard pressed to find any footage of Stoltz in Back the Future outside of a DVD feature. But did you know that Stoltz actually did make it into the movie?

Thomas F. Wilson, who plays Biff Tannen, revealed that it was actually Stoltz's fist who hit him in the diner scene in 1955.

It's my belief that Eric Stoltz's fist punches me in the 50's cafe, because I do not think we re-shot that, because it was a close up of me.

Here's the scene in question:

2. The movie was almost titled 'Spaceman from Pluto'

Universal Pictures head Sid Sheinberg apparently didn't like the original title, saying no one would see a movie with the word "future" in the title. He suggested to Robert Zemeckis that they change the title to Spaceman from Pluto to play into the movie's joke of Marty-as-an-alien. So instead of Marty uttering the line, "I'm Darth Vader from the Planet Vulcan" to his terrified father, he would say ... "I'm a spaceman from the planet Pluto." Luckily, Steven Spielberg quickly shot him down.

3. In early drafts of the script, the time machine was a refrigerator

And they were going to literally nuke the fridge.

The time machine looked like an old refrigerator that was powered by a power converter. To get back to the present day, Marty and Doc (Professor Brown in this draft) had to travel to a Nevada atomic test site to power the machine. Budget constraints forced Zemeckis to rewrite the climactic scene, and the team decided to change the time machine to a DeLorean because of its futuristic look and because they didn't want children who watched the film to start climbing into fridges.

4. Einstein was originally a chimpanzee

This time, Sheinberg did right by declaring that no movie with a chimpanzee has ever been a success. Einstein was changed to a sheepdog.

5. Ronald Reagan was a fan

Ronald Reagan was so amused by the movie's in-joke about his presidential run -- with Doc incredulous at the idea that an actor could become president -- that he asked his projectionist to replay the scene.

Reagan even referenced the movie in his 1986 State of the Union address, saying, "As they said in the film Back to the Future, ‘Where we’re going, we don’t need roads.'"

6. This was Billy Zane's first film role

He played one of Biff's cronies, Match, in both Back to the Future and Back to the Future II.

7. And Back to the Future II was Elijah Wood's film debut

He was that kid playing an arcade game in the future cafe!

8. In Back to the Future III, Michael J. Fox almost really suffocated

Remember that scene where Marty gets dragged behind a horse then gets hanged by his neck for a scary couple seconds? Well, that wasn't acting. In his book Lucky Man, Fox said that he was really suffocated, losing consciousness for a couple seconds before "Bob Zemeckis, fan of mine that he was, realized even I wasn't that good an actor."

9. ZZ Top gave an impromptu concert on the set of Back to the Future III

Yes, the rock band made a cameo in Back to the Future III, but they also performed a spontaneous concert for the cast and crew while they were waiting for a camera to be repaired. After two hours of playing, Robert Zemeckis revealed that the camera had been fixed, but didn't want to stop the party.

10. Jaws 19 is shown to be directed by Max Spielberg, the real life son of Steven Spielberg

Like father, like son.

11. Crispin Glover didn't actually appear in the last two films

Glover was reportedly angry at the materialistic ending of the first film and refused to appear in the second. Or it may have been because of paycheck issues. Whatever the case, the guy who played old George McFly in 2015 actually was a doppelganger with tons of makeup and facial prosthetics caked on him. For other scenes, Zemeckis cut together clips of Glover's previous films to fill in holes.

12. Biff's catchphrases were improvised

Thomas F. Wilson did in fact coin the terms, "Make like a tree and get out of here," and "butthead." He even made a postcard fact sheet confirming it just for you.

13. Some of the shots of the dog in the car were actually of a man in a dog suit

No sheepdogs were harmed in the making of this film.

14. Three more Marty's that could have been

Before there was Stoltz, John Cusack, C. Thomas Howell were in talks to play Marty. Johnny Depp apparently auditioned but the poor guy's reading wasn't even remembered by writer Bob Gale. Ralph Macchio turned down the role, thinking the movie was about "A kid, a car and plutonium pills."

15. Three more Doc Brown's who could have been

Jeff Goldblum, John Lithgow and Dudley Moore were all considered for Doc Brown.