15 Massive Leaks That Spoiled Marvel Movies

Since at least the end of Phase One of the Marvel Cinematic Universe, Kevin Feige and Marvel Studios have had to contend with internet rumors, misinformation, and leaks. There was a market for this sort of spoilery content online even before the explosion of social media, when Feige was just an associate producer on "X-Men" learning that someone had snagged and shared a photo of Hugh Jackman in his Wolverine costume.

Today, it's harder than ever for Marvel to keep spoilers at bay. Massive communities have assembled online just to compile and cross-reference every potential leak shared by film journalists and influencers (many of whom have more or less built entire followings based on their ability to stay one step ahead of the MCU). When a crew member so much as shares a potentially incriminating photo, there's a system in place to dissect and disseminate that information as much and as widely as possible. So, as we continue to endure the latest tsunami of potential leaks from upcoming "Avengers" films, we've taken a look back at the most outrageous breaches of secrecy in the MCU thus far.

As longtime master builders know all too well, LEGO will never miss out on an opportunity to release a Hulkbuster set when Marvel gives it the opening. Having made its long-awaited debut in "Avengers: Age of Ultron," fans were overjoyed to see the oversized Iron Man armor (with a noticeable Stark upgrade, of course) make a return appearance in the first trailer for "Avengers: Infinity War."

It's safe to say that most assumed that Robert Downey Jr.'s Tony Stark would be the one piloting the armor as he had in "Age of Ultron" — that is, until LEGO unveiled its lineup of "Infinity War" playsets ahead of the film's release. MCU fans were quick to point out that the "Hulkbuster Smash-Up" set did not include a Stark minifigure, but rather one for Mark Ruffalo's Bruce Banner. It sparked speculation as to why Banner would wear Tony's suit instead of simply Hulking out, though it wasn't widely guessed that Banner would actually be unable to transform for the majority of the movie.

Though Marvel ultimately did a pretty impressive job keeping the major spoilers of "Avengers: Infinity War" under wraps until the film's release, nothing compares to the near-total lockdown it maintained for "Avengers: Endgame." The title alone was kept a secret until the first trailer dropped just over three months ahead of the film's premiere, and the premise and overall plot were shrouded in mystery — not even the LEGO sets were helpful.

There was, however, one unauthorized photographer who managed to snap several illicit photos of Robert Downey Jr., Chris Evans, Mark Ruffalo, and Paul Rudd while they were filming a scene together set in the streets of New York, dropping them online prior to the release of "Infinity War." Most notable at the time was Evans' costume — not the Captain America suit he'd worn in "Captain America: Civil War" or the tattered garb seen in trailers for "Infinity War," but his pristine outfit from the original "Avengers" film in 2012. Combined with the presence of Rudd's Scott Lang (whose "Ant-Man" movie had vaguely established some nascent time travel mechanics already) and the matching, suspiciously sci-fi-looking watches worn by the group, fans were already able to start putting the pieces of the time heist plot together over a year before "Endgame" hit theaters.

One could describe it as poetic that "Deadpool and Wolverine" was subjected to as many leaks as it was, given Ryan Reynolds was infamously only able to get the "Deadpool" franchise off the ground because "someone" leaked that test footage over a decade ago. All jokes aside, "Deadpool and Wolverine" is arguably one of the rare instances where leaks were ultimately good for a movie, and not only because one of them convinced Reynolds to change the title from "Deadpool and Friend."

Director Shawn Levy was willing to sacrifice significant on-set secrecy in order to film the movie's wasteland sequences on location, avoiding giving it the green screen treatment and/or staging everything in ILM's Volume (the latter technique having cheapened the final look of "Thor: Love and Thunder"). This resulted in a whole gallery's worth of leaked set photos, revealing everything from Hugh Jackman's comic-accurate Wolverine suit to a few of the lesser "X-Men" cameos. And with the discarded 20th Century Fox sculpture positioned in the background of several shots, it wasn't hard to deduce that "Deadpool and Wolverine" was going full Multiverse of Meta using the Void (which was introduced in "Loki"). At the end of the day, these spoilers took away far less from the film than a fake background on a soundstage likely would have.

Tom Holland gets plenty of flack for potentially being the most prolific leaker in the Marvel Cinematic Universe, but he was far from the biggest liability in terms of spoilers when it came to "Spider-Man: No Way Home." Jamie Foxx broke the Marvel fandom with a shocking Instagram announcement in October of 2020 when he revealed that he would be reprising his role as Electro from "The Amazing Spider-Man 2" in the then-upcoming film.

An Instagram caption underneath some very unofficial fan art is hardly how Marvel Studios would have preferred to share such multiversal news with its fanbase, especially since said art also showcased Holland's Spider-Man standing with Andrew Garfield and Tobey Maguire's web-slingers. Foxx deleted the post soon after it went up, but he seemingly wasn't the only offender in the cast. Later, Doc Ock actor Alfred Molina also dropped his own casting announcement rather casually in an otherwise unrelated interview with Variety.

Foxx and Molina's "No Way Home" casting alone was enough to get Marvel fans thinking about the potential for a multiversal crossover between the three live-action "Spider-Man" universes, and Foxx's fan art, in particular, explicitly laid out why such a crossover could see the unlikely return of Garfield and Maguire's Spider-Men. The market for "No Way Home" leaks was red hot from that point on, with communities like the r/MarvelStudiosSpoilers subreddit compiling and ultimately verifying even the tiniest of online rumors. Before the film's release, it had every major plot point and cameo listed on a single megathread.

The biggest leak of all was a set photo that very clearly showed Garfield in-costume as Spider-Man on a set that couldn't be traced back to either "Amazing Spider-Man" movie. The virality of the image was so undeniable that Garfield himself — who, again, wasn't publicly attached to the film in any way at this point — had to call in to Jimmy Fallon to deny his involvement, claiming the image was photoshopped. Whether or not that lie was truly successful, we leave to our readers to decide. Regardless, Kevin Feige felt the leaks didn't ruin Garfield and Maguire's Marvel comeback, arguing that the movie was powerful enough on its own merits to excite without keeping every detail a surprise.

Speaking of r/MarvelStudiosSpoilers: The infamous scoop subreddit managed to keep itself out of Marvel Studios' direct sights, even as it continued to amass more and more leaked material with each new release. However, the party finally came to a (temporary) end when someone got the wise idea to post the actual script for "Ant-Man and the Wasp: Quantumania" on the subreddit for the world to see.

Hopefully, the Reddit karma was worth the very real karma of Marvel suddenly choosing to retaliate. The studio formally subpoenaed both Reddit and Google (which hosted the script via Google Drive) for any information that could help it track down the source of the leak. It was of the House of Ideas' most legally aggressive retaliations since its legal maneuvering over the leaked trailer for "Avengers: Age of Ultron." This led to r/MarvelStudiosSpoilers shutting down for a time, though it has since reopened with stricter content moderation and submission guidelines.

As much of a headache as that "Ant-Man and the Wasp" script leak was for Marvel, it, at the very least, only involved 60 pages of one draft of a screenplay. In fact, it may have primarily given the studio some anxiety-inducing flashbacks to a far more dramatic breach, in which someone managed to snatch up the full, 129-page shooting script for the original "Avengers" film — specifically, a copy that belonged to none other than Samuel L. Jackson.

Speaking on Entertainment Weekly's Around the Table series in 2023, Jackson stated that someone working at the Canadian production office had printed out his copy of the screenplay before quitting and fleeing the country. This person later brazenly posted pictures of the script online in an attempt to negotiate a sale — leading Marvel to set up an ultimately unsuccessful sting operation to "buy" the screenplay back.

Presumably, anyone allowed within 100 yards of a Marvel Studios set would be carefully instructed not to share photos (even privately) of them in their costumes. This would surely go double for a film as protected as "Avengers: Endgame."

And yet, somehow, about six months ahead of that movie's release, a photo of Gwyneth Paltrow as Pepper Potts — dressed for the first time in her Rescue armor from the comics — made its way onto social media. The image almost certainly appears to be a selfie taken by Paltrow in front of a green screen, likely from the very soundstage (or one of them, at least) where the final battle between the Avengers and Thanos (Josh Brolin) was filmed. In Paltrow's defense, the suit wasn't the best kept secret from "Endgame" regardless, with its full design ultimately being revealed via a leaked action figure.

For an action star like Frank Grillo, it's fortunate that he found a home in James Gunn's DC Universe, given how quietly heated his MCU exit was. While teasing his then-rumored casting as Rick Flag Sr. in "Creature Commandos" in 2023, the actor shared that he felt Marvel had wasted the potential of Brock Rumlow — aka the Hydra soldier Crossbones, whom Grillo only played in a supporting capacity before the character was killed in an inglorious blaze in "Captain America: Civil War."

Though Grillo agreed to reprise his role for a key scene in "Avengers: Endgame," his bitterness was already obvious. He spoiled his own return six months before the film arrived, even revealing that it would only be through flashbacks — which, albeit unintentionally, added further fuel to speculations concerning the film's guarded time travel storyline. As he put it at the time, "I'm allowed to say whatever I want because I'm never doing another Marvel movie."

Grillo was not, in fact, allowed to say whatever he wanted, and he apparently got so much heat from Marvel over his comments that he no longer talks about upcoming comic book projects, even at DC. It also turned out he wasn't as finished with the MCU as he thought. Eventually, tensions cooled enough for Grillo to be invited back for several episodes of "What If...?," and the actor has since indicated that he's open to future MCU appearances too.

Even if secretly-cast Marvel actors go to great lengths to protect their involvement in future movies, there's always a chance an understandably excited peer will spoil it all anyway. Indeed, before "Avengers: Endgame" was released, Sebastian Stan dropped several minor spoilers by expressing his awe over sharing a set with Samuel L. Jackson, Michael Douglas, and Michelle Pfeiffer, none of whom were confirmed for the cast at the time. Meanwhile, Evangeline Lilly went so far as to tag Corey Stoll in a social media post about "Ant-Man and the Wasp: Quantumania," spoiling his involvement with the sequel.

Still, no casting spoiler was as jaw-dropping — or unintentionally hilarious — as "Invincible" creator Robert Kirkman's simultaneously reckless and nonchalant reveal that Steven Yeun was going to star in "Thunderbolts*" as the Sentry. He casually dropped that bit of news during a routine livestream, apparently so out-of-the-loop with Marvel that he assumed fans already knew. And while Yeun ultimately dropped out due to scheduling conflicts, Kirkman was still on the hook for spoiling that the Sentry would appear in the film at all, surely adding to his admitted feelings of guilt and anxiety over the debacle. Given how coy the movie's marketing was with the character even after Lewis Pullman replaced Yeun, it seems as though Marvel hoped to save that reveal for theaters.

Though Reddit might've become a one-stop destination to read about any and all leaks coming out of Marvel Studios, it's rarely the actual source. Rather, most leaks seem to almost come out of thin air, so much so that we often wonder what "leaks" are just lucky, educated guesses.

Such was the case with a 2022 report from The Illuminerdi (an independent entertainment news site that has seemingly gone dark since then) that got picked up by mainstream outlets and claimed to have confirmed that John Krasinski would be appearing in "Doctor Strange in the Multiverse of Madness." But while vaguely reporting certain popular fancastings as fact is fairly common in the Comic Book Movie Scoops Industrial Complex, Illuminerdi was correct in asserting that the scope of Krasinski's role would be a cameo. Regardless, the leak received enough coverage that many fans went into theaters fully expecting a Fantastic surprise.

While "Avengers" fans were fairly certain they hadn't seen the last of the Hulk in the opening scene of "Infinity War," the tension of his return was significantly undercut by pre-production concept art. A key image not only spoiled the character fighting alongside the rest of the Avengers once more, but it also showed him wearing a suspiciously put-together costume. Marvel readers quickly deduced that this meant the film would feature some version of the "Professor Hulk" persona previously seen in Marvel's comics.

The art also spoiled a few more predictable plot developments. Tony Stark and Nebula (Karen Gillan) are side-by-side after being stranded together at the end of "Infinity War," while Ant-Man is shown to have escaped the Quantum Realm. On the other hand, Chris Hemsworth's Thor is curiously depicted looking the way he did in "Infinity War," preserving his own unexpected transformation in "Endgame."

As another part of the pre-production process for MCU movies, Marvel Studios will have CGI animators make crude renderings of key sequences and fight scenes. This process, known as "pre-visualization," allows the film's creatives to choreograph and stage particularly difficult moments that will ultimately require a heavy amount of post-production VFX work to complete.

Unfortunately, this means that some of the most exciting moments in the MCU — like, for example, Patrick Stewart's Professor X returning for a battle with a fully powered Scarlet Witch (Elizabeth Olsen) in "Doctor Strange in the Multiverse of Madness" — are sometimes leaked in a relatively unrefined state. This instance was especially disappointing since fans didn't know just yet that either Stewart or Charles Xavier would be coming back at all. Not to mention, this laid the groundwork for further speculation about the film's multiversal plot.

Having mostly controlled any leaks for a full year, Marvel Studios was devastated when — just a week out from the film's April 2019 release — someone managed to post several minutes of footage from "Avengers: Endgame" online. It wasn't just some random bits, either. Rather, it was a carefully edited compilation of the film's biggest reveals (a spoiler sizzle reel, essentially).

The footage included Thor's new look (as well as his return to Asgard), Hulk using the obviously Stark-designed Nano Gauntlet, snapped characters returning via Doctor Strange's portals, and even Captain America lifting Mjolnir. If you managed to dodge the spoilers online, you weren't alone. As disappointed as Kevin Feige was that someone seemed to have violated the trust of an advanced screening, he was pleased to see that the overall reaction from fans was to ignore and avoid the footage entirely to preserve a once-in-a-lifetime theatrical experience.

The biggest twist ending in the Marvel Cinematic Universe so far is undoubtedly the end of "Avengers: Infinity War," which shockingly killed off half the characters in the franchise with a single snap. It's an ending so perfect, so delicate, so spoilerable that you'd be reasonably wary of entrusting it to, say, Mark Ruffalo, a notorious leaker who once accidentally live-streamed the premiere of "Thor: Ragnarok" from his phone.

And yet, perhaps because he's so known for accidentally dropping spoilers, everyone assumed he was trolling for marketing when he bluntly said that "Infinity War" ended with everyone dying during a promotional interview. Don Cheadle was the only cast member with him, his immediate "Dude!" of disbelief apparently genuine as Ruffalo began to panic that he had potentially said too much. (Y'know, by revealing how the movie ends.) That said, people barely paid attention to it compared to the other leaks on this list, arguably making Ruffalo's hilariously flippant quip the greatest Marvel spoiler of all time.