'Avengers: Endgame' theory revealed Iron Man's secret weapon against Thanos

We always knew time travel would be important, but how?


Marvel pulled off one of the biggest cliffhangers of all time with Avengers: Infinity War, forcing fans to wait a full year before Endgame provided some resolution. In those long, long 12 months, we couldn’t help but speculate over how the final battle against Thanos would play out — be it time travel or Iron Man’s “proton cannon.”

Read more of Inverse’s 19 favorite fan theories of 2019. Oh, and spoilers ahead.

19. Loki somehow survived and shows up in Avengers: Endgame

Avengers: Endgame fans knew long in advance that the movie would include a bunch of time travel, and they were all right. However, undoing Thanos’ snap would only serve to bring back those lost in his initial Snap. Loki was not one of those people. After all, the God of Mischief died on the Asgardian ship prior to the Mad Titans’ descent to Earth.

Still, fans had hope that Loki would somehow return, even while directors Anthony and Joe Russo confirmed that Loki was actually gone for good. I’m not saying the internet brought him back to life, but Endgame did manage to cleverly resurrect him through time travel. After the Avengers botched their mission in 2012, that version of Loki was able to steal the Tesseract and poof out of there. So, Loki gets to be alive in another dimension/era somewhere and dead in the present all at once. Now that the God of Mischief is getting his own Disney+ show, the internet’s wish came true.

Verdict: The internet is powerful

Mae Abdulbaki


18. Iron Man is gonna shoot Thanos with a proton cannon

Marvel fans who grew up playing Marvel vs. Capcom 2 and learned that Iron Man’s Proton Cannon might appear in Avengers: Endgame were ultimately left disappointed. In October 2018, set photos of Avengers: Endgame leaked online, showing what looked like a giant cannon. Hardcore fans noticed that this cannon looked an awful lot like the one Iron Man wielded in the classic arcade fighting game, Marvel vs. Capcom 2.

Fans were so into the theory, we at Inverse even reached out to a professor of nuclear physics at the University of Notre Dame, who vetted whether the “cannon” could be real or not.

Turns out, fans didn’t have to wait until Endgame to learn what it was. The “cannon” was just a background prop on Rhodey’s (Don Cheadle) desk at Avengers HQ. It was present in 2018’s Avengers: Infinity War, and showed up again in Avengers: Endgame, still just as a prop. It was never used, let alone fired, even in the big battle against Thanos.

Not that the Avengers needed a cannon. After all, they already had a Hulk.

Verdict: Wrong

Eric Francisco

Dr. Stephen Strange experiences the quantum realm in 'Doctor Strange.'


17. The quantum realm would unlock time travel in Avengers: Endgame

The Marvel Cinematic Universe established the Quantum Realm in the first Ant-Man, a subatomic plane of existence that’s super tiny. It was also featured in Doctor Strange, and by the time it became an important focus of Ant-Man and the Wasp with its casual mention of something called a “time vortex,” we all assumed it could lead to time travel.

In the coffee table book called Marvel Studios: The First Ten Years, Marvel Studios boss Kevin Feige teased “there are all sorts of adventures to be had at that level, which perhaps we will explore in another film,” which felt to many of us like a sly confirmation that Avengers: Endgame would involve the Quantum Realm. Hank Pym actor Michael Douglas also straight-up confirmed in October 2018 that the Quantum Realm was “key” in the MCU moving forward.

Were any of us truly surprised by all of the Quantum Realm time travel shenanigans in Avengers: Endgame by the time it came out?

Verdict: 100% accurate.

Corey Plante


Warner Bros.

16. In Joker, Arthur Fleck inspired the real Joker

Todd Phillips’ standalone DC Comics origin story didn’t exactly lend itself to fan theories, but one early bit of speculation had remarkable staying power. Before Joker even hit theaters, one fan wondered if the character portrayed by Joaquin Phoenix was the real Joker or just some creepy clown who inspired the iconic Batman villain.

After Joker released, this theory started gaining even more traction. The fact that Phoenix’s Arthur Fleck inspires an entire mob of rioters in clown masks definitely fits, but it wasn’t until Phillips himself mentioned the theory that it really took off.

“Maybe Joaquin’s character inspired the Joker,” Phillips told the Los Angeles Times. “You don’t really know. His last line in the movie is, ‘You wouldn’t get it.’ There’s a lot going on in there that’s interesting.”

We’re pretty sure that’s the closest this Joker theory will ever get to being considered “canon.”

Verdict: Confirmed

Jake Kleinman

Emilia Clarke and Henry Golding star in 'Last Christmas.'

Universal Pictures

15. The title of Last Christmas gave away the twist

Not all fan theories require encyclopedic knowledge of a cinematic universe. Sometimes, a movie makes itself so obvious, the internet can collectively, and accurately, agree on the plot twist months before its release just by watching the trailer. Case in point: Last Christmas, the a-dork-able Christmas rom-com starring Emilia Clarke and Henry Golding.

When the trailer for the Paul Feig-directed Christmas comedy debuted in a sweltering August, the internet saw through its trickery right away. On platforms like Twitter, people guessed that Henry Golding’s impossibly charming male lead, Tom, had to be dead, an angel sent from above to help Kate (Emilia Clarke), an aimless twenty-something Londoner who barely survived a harrowing health scare, and reassure her that life is worth living.

The twist: The internet was totally, 100% right, down to the T. It was almost shocking how not shocking the film’s plot turned out to be. But as romantic comedies have ceased to exist at the cineplex (instead finding homes on streaming platforms like Netflix), Last Christmas was a welcome, if predictable warm hug that came just a little too early for critics to feel its holiday joy. Audiences, meanwhile, were more festive, giving the film $101 million at the worldwide box office. Last Christmas was, and is, proof that even an utterly predictable story still works if you let it.

Verdict: Scary accurate

Eric Francisco

Read more of Inverse’s 19 favorite fan theories of 2019.

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