10 Major MCU Spoilers That Leaked Before the Movie Came Out

One of the biggest hooks for fans of the Marvel Cinematic Universe is the thick veil of secrecy around every new film that the franchise releases. Each Marvel movie arrives with the possibility of major character crossover cameos, connections to the past and/or future of the larger franchise universe, as well as any number of comic book-style twists, turns, and cliffhanger shocks. 

Without a doubt, Marvel Studios is one of the best to ever do it when it comes to preserving franchise secrets – as every single one of their film actors (from headling stars to bit players) has made clear, over the years. That all said, even with the best media training and PR planning possible, Marvel Studios has inevitably seen its secrets leak out before some of the biggest MCU films 

Script Leaks

This one deserves its own sub-entry in the list, as it is a proud tradition of the MCU, going right back to the start. 

Virtually every MCU film has seen some version of its script leak at some point. One milestone example was Marvel Studios setting up an entire sting operation on someone who got hold of Samuel L. Jackson’s Avengers script; more recent examples would be the script for Doctor Strange and the Multiverse of Madness, which had the Internet buzzing about Marvel’s Illuminati – or all the twists of Ant-Man and the Wasp: Quantumania, which were all over social media.

If you take a quick look around Redditt today, you will still find alleged script leaks for numerous upcoming MCU films all over the place – for anyone who wants to go looking. 

Cameos BLOWN

Right behind script leaks deserving a sub-entry on this list are MCU cameos that have been blown before the film is released. 

To be fair, keeping MCU cameos secret is nearly impossible in the context of the modern world. If actors have to show up to exterior sets, paparazzi snap a picture, and fans can instantly put the pieces together. Moreover, Marvel Studios can’t avoid keeping cameo actors’ names off of official documentation (press packets); trailers and promos are easy lanes for spoilers; and it gets even trickier trying to get cameo actors into red-carpet premiere events with the entire world watching.

Meanwhile, diehard MCU fans and news outlets go so far as to track actors’ movements over social media: if an actor goes anywhere near the location of an MCU film production during a shoot, the cameo theories will begin. MCU actors don’t make it easy, either: like when Sebastian Stan revealed that Michell Pifeffer’s Janet Van Dyne would return in Avengers: Endgame. 

Eye Was The Prize

Sometimes, MCU spoilers are not so much spoilers as they are unsolicited teases that get fans way overhyped – and then lead to massive disappointment.

 Case in point: Samuel L. Jackson promised Marvel fans that Captain Marvel would finally answer one big mystery of MCU lore: how Nick Fury lost his eye: “You’ll see, specifically, the origin of what happened to his eye.”

Marvel fans went into the theater to see Captain Marvel expecting a compelling backstory that would bring honor and epicness to Fury’s lost eye. Instead, we got one of those aforementioned divisive comedic post-credits scenes, which revealed that Goose the pet Flerken was responsible for disfiguring Fury.

One has to wonder if that humorous piece of MCU lore would’ve gone over better if fans had little to no expectations about Fury’s eye, going in…

Thor: Bootleg

One of the most extensive (and arguably hilarious) MCU leaks happened when the infamous spoilers king himself, Mark Ruffalo, accidentally bootlegged the first 20 minutes of Thor: Ragnarok by live-streaming it from his phone!

Ruffalo had been live-streaming the Thor 3 premiere to promote the event, as his Hulk character was a major co-star in the film. However, when it came time to head into the theater for the premiere screening, Ruffalo tragically missed the ‘end’ button on the live-stream, put the phone in his pocket, and sat down to enjoy the movie while letting thousands of fans hear him do it. 

Despite a barrage of messages from fans and colleagues, Ruffalo didn’t know what was happening until a Disney rep physically tracked him down in the audience and had him do what so many modern moviegoers should: turn off his phone. 

The Cross Conspiracy

It’s wild how even a tiny MCU leak can eventually become a flood. Case in point: Ant-Man and the Wasp: Quantumania. During pre-production on Ant-Man 3, franchise star Evangeline Lily dropped a major casting spoiler while shouting out her co-stars on Instagram – including actor Corey Stoll. 

Stoll played villain Darren Cross/Yellowjacket in the first Ant-Man film, but was seemingly killed at the end of it. Stoll’s return raised some major questions about Ant-Man 3; it didn’t take long for corresponding rumors of MODOK getting a new MCU origin to make fans realize this reveal was coming. A lot of fans wished and hoped against it – and the actual reveal was even weirder than anyone could’ve imagined. 

Avengers Assemble…for Shawarma

When Marvel’s Avengers (2012) came out, it was a milestone achievement in entertainment. Besides seeing the team-up of characters from three different film franchises (Thor, Captain America, Iron Man), fans were eager to learn how the post-credits scene for Avengers would propel the MCU forward into its next era. 

While the Thanos reveal leaked into the deeper circles of fandom, Robert Downey Jr. got major attention at a press conference when he spoiled the fact that the Avengers cast had reconvened just before the film’s release, to shoot a top-secret final scene. 

Downey’s early leak of the Avengers post-credits scene got fans buzzing with theories. That’s why the reception was somewhat mixed when it was ultimately revealed that the scene was a comedic one, featuring the Avengers eating a Shawarma meal that Tony Stark had been hungry for during the Battle of New York. 

MCU comedic post-credits scenes have been getting as many eye-rolls as laughs, ever since. 

Doing the Time-Warp

The year-long span between Avengers: Infinity War and Avengers: Endgame left MCU fans with nothing to do BUT try to dig for SPOILERS. One of the biggest leaks was that Endgame would using an ambitious time-travel plot to explain how the Avengers defeat Thanos and the Infinity Gauntlet. 

The leaks came from several sources, including script details that leaked – as well as individual MCU actors who let it slip. Tom Holland let it slip early that the Quantum Realm would be a major factor in Endgame; Samuel L. Jackson spoke too soon in saying that Briel Larson’s Captain Marvel and her time-travel powers could be crucial to Endgame. Captain America movie actor Frank Grillo didn’t hold back, revealing that his character Crossbones would return for Endgame, despite being dead in the present-day era of the MCU. 

All those actor leaks – combined with script leaks and rumors – had a lot of MCU fans ready for a Back to the Future sci-fi story in Endgame, long before it came out. 

‘Spoiling The End’ Game

Right along with major Avengers: Endgame plot details and/or cameos was the almost comical deluge of spoilers about the ending of the film that leaked from various sources. Chris Evans spoiled Steve Rogers’ ultimate fate numerous times before Endgame game out: once during a press event where he indirectly mentioned it, and another time in a vague tweet saying goodbye to the character, which fans (including this writer) called out as a hint. 

Right along with Chris Evans were most of the Endgame cast: Mark Ruffalo also spoiled Cap’s ending;  Zoe Saldana hinted early about playing a Gamora variant;  Sebastian Stan hinted at the big gathering of characters for Tony Stark’s funeral; Mark Ruffalo spoiled Steve Rogers and Peggy Carter’s fate; Gwyneth Paltrow spoiled her Rescue armor suit debut in a set photo; while Dave Bautista and other actors all dropped early hints that their dusted characters could and/or would return. 

Avengers: Endgame may go down as the most leaky production Marvel Studios ever had just by the sheer scope of the leaks – although, there is one close competitor who could wear that crown… 

Spider-Man: Far From Secret

We now live in a world where Marvel has left us with the question “What If?… We never knew the twist of Spider-Man: No Way Home before it came out?” 

The blame for this one lies with pretty much the entirety of the film industry. The studios and PR teams that let “leaks” happen to muster up hype; the merchandisers who push revealing merch before the film is out; the endless list of click-hungry pundits and publications that ran spoiler images to gain (momentary) spikes in site traffic – and then there was actor Alfred Molina (Doc Ock) who spoiled his own return during an interview he did early on into No Way Home’s production. 

For those lucky few who got to see Spider-Man: No Way Home without knowing the big secret(s) – but still understood the milestone impact of the film – they got an MCU experience that was truly transcendent! 

EVERYBODY DIES

To this day, the biggest, most flagrant, MCU leak of them all came from the cast of Avengers: Infinity War – and forever marked both Mark Ruffalo (Hulk) and Tom Holland (Spider-Man) as major PR liabilities. 

Mark Ruffalo blew the proverbial bag during a 2017 interview with GMA, alongside War Machine actor Don Cheadle. Ruffalo outright spoiled the gut-wrenching ending of Inifnity War, while discussing the film (and MCU movies in general): 

“Let me just say this; Like every other Marvel movie, it doesn’t end well for the superheroes,” Ruffalo said at the time. “Wait until you see this next one. Everybody dies.”

The terminology was general enough that there was some spin that the actor was joking. However, MCU fans could tell from Cheadle’s reaction and body language that itr was no joke, at all. 

Tom Holland’s faux pas was more personally mortifying: the actor was attending an event on the eve of Inifnity War’s release in theaters – an event he thought was taking place after a screening of the film. When Holland ran on stage yelling to the crowd not to worry, “I’m alive!” he realized to his horror that he had just spoiled the biggest death scene in MCU history (up to that point). 

Brutal for the actors. Brutal for everyone.