Movie leaks aren't anything new. Set news and spy photos have been a part of movie news for decades, but one thing important did change recently: the Internet. With the ability to spread information at a lightning-fast rate, movie spoilers and behind the scenes news began leaking faster and faster. These days, it seems like you already know everything about the movie before you even go to the theaters. We've reached an era in which everything from set photos to trailers to even just the entire movie is sneakily made available days, weeks, or even months before a film's actual release.

How a leak affects a movie can depend on a number of factors. Some huge, big budget releases can survive a leak no problem. Some can actually see the film improve dramatically based off the buzz a strong leak can create, like an unexpected character appearance or a script being better than expected. Others can suffer greatly, with news turning fans sour on a film before it even hits theaters, or even worse the entire movie being freely distributed and critically panned before it touches the box office. Movies succeed or flop based on these leaks, but it's not easy to tell which one is going to be which. We've taken a look at 10 instances of each for the purpose of this list, tearing apart some of the biggest superhero movie leaks of the past few years to highlight how these helped or hurt the films in the long run.

Spoiler Warning: This article contains possible spoilers for upcoming releases such as Aquaman and Avengers 4

20 SPOILED: JUSTICE LEAGUE (OBVIOUSLY) RESURRECTS SUPERMAN

Six movie Justice Leaguers

There was a really weird, concentrated effort to cover up Superman's appearance in Justice League that didn't really make sense. After all, he was front and center of the first released publicity still for the film, alongside other members of the League. But after that, Superman was kept out of all the film's marketing until after release, when he was added to posters and marquees.

Of course, several key elements of Superman's appearance leaked before the film came out. Storyboards included sequences where Superman appeared wearing a black version of his suit, scenes which were ultimately cut. Later still, the sequence where a resurrected Superman faced off against the League would leak, spoiling one of the film's set-piece battles.

19 SAVED: THE BIRTH OF THE STINGER IS THANKS TO LEAKS

nick-fury-smiles

Jon Favreau had a big surprise planned for Iron Man moviegoers. A scene quietly filmed to run following the film's credits would bring Samuel L. Jackson in as S.H.I.E.L.D. agent Nick Fury, something that would give birth to a wider universe of films. But it leaked before the film's release, and the surprise was seemingly ruined.

Frustrated by this, Favreau decided to one-up viewers. He pulled the scene from advance premieres, and had it added back in during the theatrical release. The result was a surprise that caught viewers off-guard and started the trend of post-credit scenes that have kept comics fans guessing and theater ushers waiting for 10 years now.

18 SPOILED: AQUAMAN'S COSTUME CHOICES SPOILED BY TOYS

Aquaman trailer

Updating Aquaman is pretty tough, as most fans still think of him from his Super Friends days. Justice League managed to somewhat successfully skirt the issue. Decking Arthur Curry out in golden Atlantean armor for his appearance in the film, the modern Aquaman looked right at home with his Justice League brethren.

However, it appears to be planned for the character to don his classic orange and gold costume for the upcoming Aquaman solo film. Any attempt at a surprise for this was ruined pretty quickly, as prototype toys and statues showed off at conventions feature the character in the film's updated take on the classic Aquaman attire.

17 SAVED: AVENGERS 4: CAP'S CLASSIC SCALES

Captain-America-The-Winter-Soldier

There are a lot of details that go missing when you make comic book movie costumes. None were as noticeable as Captain America, though. Traditionally, the good Captain's uniform has featured chainmail armor for his top, a detail which many artists gloss over.

For the MCU, Cap's suit was transitioned to a more traditional design. Though he wore a fairly gaudy rendition of his classic look for The Avengers, later movies would put him in a padded, almost motorcycle jacket type outfit. Recently though, Avengers 4 costuming pictures began to trickle out. One in particular highlighted Cap's new costume, which included a chainmail pattern to his armor for the first time.

16 SPOILED: X-MEN ORIGINS WOLVERINE TANKED BY A LEAK

X-Men Origins Wolverine

In all honesty, X-Men Origins: Wolverine was most likely doomed from the start. Despite the star power of Hugh Jackman, Liev Schreiber and Ryan Reynolds, the film appeared to have a number of problems from the beginning. The film struggled to find its footing, as the dismal performance and reception of X-Men: The Last Stand put the franchise's future in doubt.

But the worst was yet to come. Just one month before the film was due for wide release, an unfinished work copy leaked onto the Internet. Downloaded by millions, fans were quick to dismiss the film's quality after viewing, with 20th Century Fox blaming the leaked copy's availability for the film's poor box office performance.

15 SAVED: SUICIDE SQUAD: BATMAN & MORE

Batman v Deadshot Suicide Squad 2

Suicide Squad managed to pin down a surprisingly strong cast, but the characters were unknowns. Fans of the comics were going to be there, but the average moviegoer really has no reason to care about Deadshot or Killer Croc. Warner Bros did have one big surprise though: the second film appearance of Ben Affleck as Batman.

They wanted to keep the cameo a secret. It was just supposed to be a surprise, much like Ezra Miller's Flash making his first in-costume appearance. Both cameos wound up leaking to the Internet weeks before release, but they honestly only helped to build the anticipation for the film.

14 SPOILED: AVENGERS 4: CLASSIC CAP, MODERN TONY

Captain America and Tony Stark in The Avengers

Any movie is going to fall prey to the horror of spy photos. Whether it's a fan with a long zoom and an advantageous position or someone on-set who wants to make a name for themselves, leaked set photos have become a fact of the movie industry.

These leaked photos can spoil massive plot elements, and one of the worst may be what happened with the upcoming Avengers 4. Being filmed back to back with Avengers: Infinity War, fans were in for a surprise to see Tony Stark, dressed and styled as he appears in modern films, alongside Captain America in his original Avengers costume. These pictures fueled speculation that Time Stone shenanigans would define the Avengers 4 story.

13 SAVED: TEENAGE EXTRATERRESTRIAL ALIENS

For a franchise as popular in the ‘90s as Teenage Mutant Ninja Turtles, they sure have had a tricky history in movies. The first feature film was a surprise hit, but the property's relationship to its own family-friendly cartoon resulted in future films being neutered to appease parents groups.

Michael Bay stepped in to helm a reboot, but it got some pretty sharp criticism before even beginning filming. A leaked script proposed the Turtles were instead aliens. They were also being hunted by a military general, who was, in fact, an alien Shredder. The script got a lot of attention, mostly bad, which is credited with the more traditional tone of the eventual reboot that Bay made.

12 SPOILED: AVENGERS 4: A NEW TEAM ASSEMBLED

Avengers 4 Concept Art

The survivors of Infinity War were few and far between, and many guesses as to who would perish and who would live were wildly inaccurate. Though the original line-up of Avengers persevered, a number of popular characters such as the Guardians of the Galaxy, Black Panther, and Spider-Man all faded away into ash.

It didn't take long for production art to leak for Avengers 4, though. One image, which was indicated to be authentic, showed the team of survivors from Wakanda, including previously in space Iron Man, Captain Marvel, and Nebula, as well as a returning Hulk, teamed up in new gear and rushing headlong into battle, confirming both the team's configuration and style.

11 SAVED: BATMAN'S INTIMIDATING SCRIPT LEAK

batman-batman-begins-with-bat-swarm

It's hard to believe there was a time where we were all worried about the next Batman movie. In the time before Batman Begins, the wound of Batman & Robin was still fresh. A lot of fans had lost faith that a decent Batman franchise would ever come around again.

What would eventually become Batman Begins and the birth of the Nolan Batman Trilogy was a ways off when the script leaked to the Internet. Titled Batman: The Intimidation Game, this script was quickly one of the most talked about Batman projects on the Internet. Fans weren't completely sold by the script alone, but it definitely helped pave the way for fans to give it a shot.

10 SPOILED: MARK RUFFALO STREAMS RAGNAROK LIVE

Mark Ruffalo as Bruce Banner in Avengers Infinity War

The Marvel Cinematic Universe's most destructive force may not be Thanos, but Mark Ruffalo's lack of impulse control. The actor has, for years now, nearly ruined major plot details for many of the MCU's biggest films. Leading into Infinity War, Ruffalo even managed to give away the ending of the film in a Good Morning America interview, though nobody took him seriously at the time.

He also was behind a pretty notable leak, but it was entirely by accident. At the premiere for Thor: Ragnarok, Ruffalo did a red carpet live stream for his Instagram followers but accidentally left the stream running. Ruffalo unknowingly streamed the first 10 minutes of Thor: Ragnarok (or, at least, the audio) to his Instagram followers.

9 SAVED: A LEAK EXPLAINS THE FORCE AWAKENS

Star wars force awakens poster

The Force Awakens met with plenty of controversies. While the general consensus was that people enjoyed the film, hardcore fans tore it apart. Many criticized it for being far too similar to A New Hope, pointing out how closely the story beats mirrored each other. One chief complaint, though, was how confusing some aspects of the film were.

Shortly after the film's release, the script actually leaked to the Internet. A rare case of a leak actually benefiting after release, the script helped to answer a lot of questions. Stage directions and notes on the scripts helped fans understand Kylo Ren's mindset after the demise of his father, or what Luke was really thinking in those final minutes.

8 SPOILED: CIVIL WAR: GIANT LEGO LEAK

Civil War Giant-Man Lego Set

You forget about it as you get older, but movies sell toys. The Marvel Cinematic Universe is no exception, with massive toy lines aimed at adult collectors and kids. They also have plenty of lucrative cross-brand deals, which is how Marvel keeps putting out Lego sets.

Lego is a big money deal, and one of the most popular toy brands out today. Unfortunately, it has leaked its share of spoilers. Most notably, the reveal of Giant Man in Captain America: Civil War was known months before it hit theaters thanks to the release of a Lego play-set depicting the film's airfield battle and explicitly including a Giant Man figure.

7 SAVED: A VISION OF A SEQUEL

Pretty much every hero in the Marvel Cinematic Universe has been an Avenger at some point, but there's a veritable who's who of characters fans want to see first. Chief among that list was The Vision. Despite being an incredibly popular character in his own right, The Vision never really had much success as a solo star.

The Vision was slated to be included in The Avengers: Age of Ultron, but Marvel was pretty coy about it. When word leaked out that he was in the film, Marvel leaned into the marketing. You never really see The Vision in most Age of Ultron marketing, at least not full-on. He's floating around in the background, teasing fans and raising excitement for what's to come.

6 SPOILED: BATMAN V SUPERMAN'S UNCEREMONIOUS TRAILER

Following Man of Steel's less than stellar reception, how Batman v Superman was going to be received was critical. The movie had to be presented under perfect conditions, top to bottom. And it did mostly okay. A quick teaser at San Diego Comic-Con and Snyder releasing the first look at Ben Affleck's Batman started the film in the right direction.

But things went awry with the first trailer. Intended to be shown during select theatrical screenings, the trailer instead leaked to YouTube. With a low video quality and with Portuguese subtitles, the trailer was the worst possible way fans could have seen this first footage and set the tone of the film's reception months before its release.

5 SAVED: CAPTAIN MARVEL'S CLASSIC COLOR

The costume a character wears can be a definitive aspect of the journey, and Carol Danvers has had quite a few. So has her predecessor, the original Captain Marvel. Spy photos for the film first dropped showing Carol in a blue and teal colored outfit, something that resembled the original Kree uniform worn by Mar-Vell.

Fans naturally went berserk, as it wasn't the iconic modern Captain Marvel costume they'd come to know and love. Some even went so far as to photoshop it to have "correct" colors. Naturally, another leak later containing character designs for Avengers 4 confirmed Captain Marvel in her modern costume, calming down many hysterical fans.

4 SPOILED: SPIDER-MAN'S BLACK SUIT (BUT NOT THAT BLACK SUIT)

Spider-Man in Homecoming

Sure, you know by now about Spider-Man's demise in Avengers: Infinity War, but did you think for a second the money train was going to stop? Sequels are big money, and Spider-Man is a household name, so of course a sequel is underway with Spider-Man: Far From Home.

Fans recently lit up Twitter when a spy shot showcased what appeared to be Spider-Man in a black suit! Of course, it doesn't appear to be the black suit, so no Venom crossovers are coming. Rather, it's an updated version of the Stealth Suit Spider-Man designed to fight Hobgoblin during the Big Time story arc.

3 SAVED: THE JOKER ON DISPLAY

Every generation has had its own interpretation of The Joker, but the latest seems to be having trouble finding its footing. Though Heath Ledger presented a tremendous update for the character, Jared Leto's turn as The Joker for Suicide Squad left a sour taste in fans' mouths.

Following the mixed reception of Suicide Squad, a Joker origin movie was announced, with Joaquin Phoenix as the latest actor to portray the Clown Prince of Crime. The first look at the character's design, a short Instagram teaser, was met with much confusion from fans with his different, more clown-like design. Fortunately, spy footage was released a few days later, helping to alleviate many concerns.

2 SPOILED: UNMASKING THE PHANTASM

It's hard to believe it, but Batman: Mask of the Phantasm may have the most infamous leak in all of superhero movies. The film, which brought the cast of the wildly popular Batman: The Animated Series together, proved to be a smash success, and made many lists as one of the best Batman films ever made.

But the film's biggest twist -- the identity of the titular Phantasm -- was spoiled by the very thing it was designed to sell: toys. The tie-in line featured a Phantasm figure proudly packaged with its removable mask off. Fans flocking to the toy aisle quickly discovered Bruce's old flame Andrea was secretly the malicious Phantasm before the film was even in theaters.

1 SAVED: DEADPOOL SAVED BY A LEAK

15 Child Stars Who Grew Up To Be Superheroes

Deadpool is an incredible success for 20th Century Fox and redefined the idea of superhero movies. No one thought an R rated superhero movie would be a success, but Deadpool absolutely crushed expectations, setting the stage for films like Logan and the inevitable Deadpool 2 to light the world on fire.

Deadpool almost didn't happen because of these reservations, but a surprise test footage leak saved that. Footage of a car fight scene, rendered in CGI and featuring Ryan Reynolds as the character, the leak blew up the Internet. The bombastic reception was so great that Fox couldn't ignore it anymore, and the rest is history.