Most of the time, when an actor gets fired from a movie, it is usually for the best. These are the times when our favorite movies might have ended up completely different had the studios opted to not go in a different direction at the last moment. Think Eric Stoltz in Back to the Future, Stuart Townsend as Aragon in Lord of the Rings, or Meghan Fox in Transformers.

However, every once in a while a major movie star gets shown the door and the decision blows up in everyone's face.

Creative differences, broken hands, drugs, a lack of leg splits, overeating, misconduct, money, mustard grease -- there are any number of reasons why an actor might get fired from a set. However, in the instances below these last-minute bailouts caused a hurricane of disaster both on-screen and off.

No actor is safe from the proverbial axe. Nor are the movies that do the swinging. Sometimes a decision that might have seemed like a good idea in the moment ends up having some pretty nasty repercussions down the road, leaving us all left to wonder what might have been.

Here are the 15 Movies That Hurt Themselves By Firing Actors.

Spider-Man - Tobey Maguire

While you wouldn't immediately peg Tobey Maguire as your friendly neighborhood Spider-Man, it somehow worked.We can probably thank 2003's Spider-Man for the current superhero craze.

It's sequel is still considered one of the best superhero movies ever made, and despite its third act being less than stellar, that movie still raked in nearly $900 million worldwide and earned a 63% score on Rotten Tomatoes.

So when Sony decided to fire Tobey and reboot the franchise it just felt wrong-- and unnecessary-- sure, those subsequent two movies turned in a profit, but what superhero film doesn't? No one wanted to see Andrew Garfield skateboard when we could watch Peter Parker dance at a jazz club.

This is probably why Garfield's Spidey is the unwanted middle child wedged between the movies of Maquire and Tom Holland.

Gravity - Robert Downey, Jr.

We're not saying that 2013's sci-fi thriller Gravity is not a great movie and a technical achievement of epic proportions. However, by firing Robert Downey Jr from playing opposite Sandra Bullock, the filmmakers destroyed what would have been an altogether different movie for entirely different-- though no less enjoyable-- reasons.

In fact, we'll go so far as to say that while Gravity is certainly commendable, it would be far more memorable, enjoyable, and enduring if RDJ had been given the freedom to bring his endearing wit to outer space.

Unfortunately, only a few days into filming it was clear that things weren't working out. According to director Alfonso Cuaron, "Robert is incredibly talented, but technological aspects of the movie presented a big obstacle to his style of acting.” 

So Robert was replaced with George Clooney, and we're left wondering what might have been.

Predator - Jean-Claude Van Damme

You might not think that the 1987's Predator suffered much from firing Jean-Claude Van Damme. However, you underestimate the awesomeness of Jean-Claude Van Damme. Because how wonderful would it have been if the Predator did roundhouse kicks and full splits?

Alas, it wasn't meant to be. Of Predator's many impressive talents, being a martial arts master is not one of them. Prior to being cast, JCVD didn't realize that he would have his face hidden behind a mask, no lines, and be invisible for most of the movie.

So when he showed up on set and was stuffed into a giant red lycra preying mantis suit (the original look), "The Muscles from Brussels" was pissed.

Never one to let his ire go unnoticed, Jean-Claude promptly let it be known that he wanted to kick Arnold Schwarzenegger in the face unencumbered and was canned after only two days of filming, replaced by Kevin Peter Hall.

Apocalypse Now - Harvey Keitel

When Apocalypse Now started filming in 1976, Harvey Keitel was playing the lead role of Willard. However, the actor's method all-in style quickly proved a wrong fit, and so just three days into shooting he was canned and replaced with Martin Sheen.

Apocalypse Now, of course, is now regarded as a masterpiece. So as far as the final movie is concerned, there's nothing disastrous about it. However, the same can't be said about what on behind-the-scenes.

Coppola pretty much went insane, entire sets got washed away in monsoons, actual bodies were used as props, Dennis Hopper was given cocaine to get through scenes, Marlon Brando was, well, Marlon Brando, and Martin Sheen ended up having a heat attack mid-shoot.

Would all this have happened if Keitel not been fired? Who can say? At the very least Sheen would've probably been saved from at least one disastrous cardiac arrest.

Demolition Man - Lori Petty

Back in the early '90s, Lori Petty was ready to breakout. From A League of Their Own to Free Willy, Point Break and the cult classic Tank Girl, she was a part of some of the era's most memorable movies.

So casting her as Lt. Lenina Huxly in 1997's futurist acton flick Demolition Man opposite Sylvester Stallone could have been her big chance, and the lucky charm the movie needed to obtain film immortality.

Unfortunately, it was not meant to be in either case. Petty was not a fan of her character and got into one too many arguments with producer Joel Silver over the writing, eventually getting the boot. The unknown Sandra Bullock stepped in and got the career boost Petty had disastrously squandered.

Also, while Bullock's part was fine, Petty would have undoubtedly brought an edgier take that would have worked nicely opposite Wesley Snipes' ridiculous mohawk.

Beverly Hills Cop - Sylvester Stallone

Before Beverly Hills Cop became a comedic breakout film for Eddie Murphy, it was going to be an even more epic '80s-esque action movie starring Sylvester Stallone. However, after Stallone was originally cast in the lead role and saw the script, he was less than impressed.

So he rewrote it himself, throwing in some much need explosions and mumbled one liners. The studio wasn't a fan of the budgetary increase this new movie called for so decided to fire Sly instead. (Though urban legend has it the real reason was because of failed negotiations over what type of orange juice was to be kept in his trailer.)

Anyone sad that they will never get to see Sylvester Stallone as Axel Foley, fret not. His unused script ended up being turned into the movie Cobra. Though, admittedly, Beverly Hills Cobra would have been so much cooler.

Romeo + Juliet - Natalie Portman

Originally, Natalie Portman was cast as the lead in Baz Luhrmann's Romeo + Juliet. Anyone who has seen Léon: The Professional would applaud the decision for what would have undoubtedly given Shakespeare's play a fun dose of spunk. However, unfortunately starring alongside Leonardo DiCaprio had its problems.

Once filming began, the filmmakers soon realized that the actress's young complexion made her look like a little girl compared to Leo, which seemed highly inappropriate. This seems about right, considering that Natalie was only 13 years-old at the time, while DiCaprio was 21.

As a result, Natalie was dismissed and the older Claire Danes was brought in. All age differences aside, you have to imagine that this movie would have been less of a by-the-numbers teen romance flick (albeit spoken in verse), than a spirited retelling with Portman at the helm.

The Lovely Bones - Ryan Gosling

Imagine getting fired from a movie because you're too fat. Now imagine that the person in question was Ryan Gosling in Hollywood.

In prepping for Peter Jackson's adaptation of the popular yet extremely morbid novel The Lovely Bones, star Ryan Gosling decided to guzzle Haagen Dazs by the shakeful and put on a bunch of weight. (Sixty pounds to be exact.) The only problem was that he never told anyone he was gong to do this.

Instead, he just showed up overweight one day to everyone's surprise. Apparently, Jackson didn't share the actor's take on the character. As Gosling tells it, "They said 'you look terrible.' And I said 'I know. Isn't that great?' -- 'No. It's not. Hit the treadmill.'"

It turned out that this was just the tip of the iceberg over their creative differences, so Gosling was sent packing and the fully toned and chiseled Mark Wahlberg was brought in instead.

The Lords of Flatbush - Richard Gere

Never heard of this move? Our point exactly. Just a few days into filming what would have been Richard Gere's movie acting debut, the soon-to-be star was fired for quarreling with half the crew and getting into fist fights with everyone else.

The fights were most notably with Sylvester Stallone, who Gere ended up throwing down with after having eaten a greasy piece of chicken in Sly's car and getting mustard on Rocky's pants.

(Hilariously, this feud has led some to speculate that it was none other than Stallone who started the infamous "gerbilling" rumor about Gere. If you don't know what we're talking about, look it up.)

Suffice to say, 1974's The Lords of Flatbush suffered without Gere and failed to find any trace of movie magic with its new lead Perry King. Who? Our point exactly.

Dirty Harry - Frank Sinatra

Could you imagine Frank Sinatra pulling out a .44 Magnum on someone and saying, "Go ahead, make my day punk." Of course not. No one but the grizzled Clint Eastwood could make criminals we their pants like that. However, amazingly, the legendary 1971 movie was originally written for ole blue eyes.

Sinatra actually had taken the part and begun prep work but soon realized he was unable to lift the massive gun on account of having broken his wrist while shooting his previous movie, The Manchurian Candidate. So he was let go and the producers brought in Clint.

Certainly the end result is not a bad one, but Dirty Harry would have been a completely different movie with Sinatra. Consider this a case of a movie destroying itself, and then replacing it with something a billion times better.

All the Money in the World - Kevin Spacey

We're not arguing that removing Kevin Spacey from All the Money in the World wasn't the right move given all the allegations swirling around the actor. However, it's pretty clear that his firing had some disastourous repercussions for the movie and its filmmakers.

Though to say Kevin Spacey simply got fired, doesn't do what happened justice. He was literally replaced. The movie had already finished shooting and its trailers released showcasing his role as J. Paul Getty.

However, once the scandal broke, director Ridley Scott made the tough (and very costly) decision to go back and frantically reshoot all Spacey's scenes with Christopher Plummer.

On top of that, it was revealed that Michele Williams only earned $80/day (totaling less than $1,000) for the reshoots, while co-star Mark Wahlberg made $1.5 million for the same exact work. In other words, it's everything wrong with Hollywood in one movie.

Valley of the Dolls - Judy Garland

For those who don't know, Valley of the Dolls was basically the 50 Shades of Grey of its time. Originally a critically panned but wildly popular book that remains to this day one of the best selling novels of all-time, the 1967 movie drew audiences in with its promise of showing young women doing scandalous things. All and all, a pretty campy affair.

However, one highlight would have been Judy Garland, who was originally cast in the supporting role of Helen Lawson. However, Garland, known for her life-long struggle with substance abuse, would reputedly show up drunk on set and was soon replaced with Susan Hayward -- a huge loss since you don't get much bigger than Judy.

Though it has since been said that director Mark Robson intentionally made Garland wait until the late afternoon to do her scenes, knowing full well that she would be drunk by that time.

Dicky Tracy - Sean Young

Best remembered for playing Rachel in the original Blade Runner, Sean Young, despite a promising early career, eventually fizzled off the screen thanks in no small part to a boisterous reputation. One last ditch effort came in 1990's Dick Tracy playing Tess, the love interest of the heroic yellow-coated cop.

Only after a week of shooting, she was out, though. The official reason from the studio was that she wasn't "maternal enough" for the role, and so was replaced by Glenne Headly.

However, Young would later claim she was fired because she repeatedly refused to sleep with lead Warren Beatty. (Beatty, who directed the movie, denied the claim.)

Dick Tracy barely made a profit despite garnering much attention as one of the first comic book adaptations, marred even further by behind-the-scenes conduct suggested by Young.

Chicken Little - Holly Hunter

Chicken Little has the distinction of being Disney's first 100% CGI movie. It did not go well and ended up leading them to just buy Pixar for $7.4 billion rather than compete.

However, would things have been different if they went with their original plan to have Chicken Little be a girl played by one of the best voices in Hollywood: Holly Hunter?

Despite having spent eight months recording her lines, Holly was replaced when it was suddenly decided that girl chickens don't sell tickets and the movie would be better as an action flick with a father-son dynamic. So the lead was rewritten and Zach Braff brought in.

Many believe that the original story was far better. Certainly tackling a female-centric chicken story would have been laudable, and give the impression that Disney wasn't just trying to do whatever they could to make money and still had some artistic integrity. Oh well.

American Sweethearts - Robert Downey Jr

Rom coms are a dime a dozen. Sure, they make the studio a quick buck but beyond that their only claim to fame is helping fill the $5 bin at Walmart. Throw Robert Downey Jr into the mix, though, and now we're talking.

So when RDJ was fired from 2001's American Sweethearts starring Julia Roberts and Catherine Zeta-Jones, it was a great day for Walmart and a sad day for the rest of us.

To be fair, Downey was facing drug charges at the time that could've landed him in prison for 6 years. He was also reputedly constantly getting loaded. So you can understand the decision, but it most likely destroyed what would've been a far more memorable movie.

In case you're wondering, Downey ended up not going back to prison and became a superhero instead. So we guess everything worked itself out in the end.

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Can you think of any other firings that completely ruined movies? Let us know in the comments!