Fan theories have sometimes would up being more intriguing than the actual direction the Marvel Cinematic Universe has taken its story in over time.

Speculating on future events and formulating theories is one of the most rewarding parts of being a fan of the Marvel Cinematic Universe, but sometimes these ideas can lead to dissatisfaction when they don’t end up coming true. Creating the concept of the cinematic universe, Marvel Studios have consistently been amazing at planting seeds of foreshadowing that pay off in a big way later on, intertwining their various properties and stories with a shared bloodline of the MCU’s continuity. There are few equivalents to the cinematic catharsis delivered when the series finally acknowledges something set up years earlier.

Of course, Marvel viewers can sometimes get ahead of themselves in looking for these big reveals ahead of time, crafting elaborate fan theories that can sometimes be more exciting than the franchise’s actual plans. Marvel Comics provide a treasure trove of characters, developments, and story beats for eagle-eyed viewers to look out for, and the rumor mills that swirl behind each upcoming MCU release can add even more fuel to the fire of speculation. Sadly, Marvel Studios can’t always live up to the high expectations of their audience of millions, leaving many fan theories ripe for adaptation by the wayside.

10. Quake Would Link Secret Invasion To Agents Of S.H.I.E.L.D.

The ABC series wouldn’t get the Netflix treatment.

After the appearance of Charlie Cox’s Daredevil and Vincent D’Onofrio’s Kingpin in the MCU, the supposed dissolution of Netflix’s TheDefenders continuity was re-examined. If Netflix’s heroes were on the table, it would make sense that ABC’s Agents of S.H.I.E.L.D. was soon to follow, and fans of the series were hopeful for recurring character Quake to be introduced to the MCU via Nick Fury’s Secret Invasion miniseries, considering the character featured prominently in the comic of the same name. Tragically, this wasn’t the case, and the ABC show continues to languish as a non-canon side story.

9. WandaVision Would Introduce Mutants Into The MCU

The series could’ve gone a long way in bringing the X-Men to the MCU.

With the MCU finally procuring the rights to the X-Men only two years prior, viewers of Marvel’s first limited series on Disney+, WandaVision, were hopeful that Scarlet Witch’s world-altering powers could bridge the gap between universes. The appearance of Evan Peters as Quicksilver in the show only made the idea seemingly more obvious, considering the Maximoff twins had a foot in the worlds of both the X-Men and the Avengers. Sadly, the potential for the series to bring mutants into the fold was squandered for a joke, revealing Peters’ character as a mere actor.

8. Spider-Man Makes A Deal With Mephisto

The Demon king’s long-awaited introduction to the MCU has yet to happen.

One of the most prolific villains in Marvel Comics, Mephisto is a demonic entity responsible for many of the franchise’s most vile acts, including the descent of Norman Osborne into the Green Goblin persona. With such heavy ties to Spider-Man, theorists were hopeful that Mephisto would be introduced into the MCU with Spider-Man: No Way Home, as Peter Parker makes a literal deal with the devil to repeal the reveal of his secret identity. However, it was Doctor Strange’ spell rather than Mephisto’s influence that would alter the world’s memories of Peter Parker, keeping Mephisto at bay.

Theorists were hopeful that Mephisto would be introduced into the MCU with Spider-Man: No Way Home.

7. Bruce Banner Would Return In World War Hulk

MCU fans got only the smallest glimpses of the iconic comic storyline.

After the Hulk was ejected into outer space following the events of Avengers: Age of Ultron, it was impossible not to draw parallels between the event and the start of the famous World War Hulk crossover event. In the comic, The Hulk is exiled from Earth by the Illuminati, only to return as a seasoned warrior capable of taking on the entire planet. Thor: Ragnarok gave only the briefest glimpses into the storyline, with teases like Hulk’s gladiator armor and the planet Sakaar, but the story was sadly never adapted in earnest by the MCU.

6. Tom Cruise Would Star As An Alternate Tony Stark

The MCU multiverse didn’t get a lot of mileage out of Iron Man

As the MCU began to introduce the multiverse, rumors began swirling of the possibility of Tom Cruise’s appearance as an alternate Iron Man variant in Doctor Strange and the Multiverse of Madness. Famously, Tom Cruise nearly played Iron Man in lieu of Robert Downey Jr., which would make his cameo as a variant Tony Stark in the Illuminati incredibly fitting. In the end though, it seems as though Marvel Studios either didn’t care or weren’t able to procure the busy Mission Impossible star as a cameo appearance, dashing the hopes of those wishing to see Cruise in Iron Man’s armor.

5. Heimdall Was The Actual Guardian Of The Soul Stone

The Infinity Stones’ locations had fans seeing clues that weren’t there.

Going into Avengers: Infinity War, the only Infinity Stone with an unknown location was the enigmatic Soul Stone. Some eagle-eyed fans noticed a fascinating pattern – the location of the other stones nearly spelled out “Thanos”, leaving only an “H” to represent the missing Soul Stone. Speculation ran rampant that Thor’s friend and Bifrost Bridge guardian Heimdall could hold the final stone, finishing the acronym and explaining the character’s yellow eyes and magic. Arguably, this would’ve been a more fitting final location than Vormir for the stone in some ways, as it would’ve put more weight behind Heimdall’s death.

4. The Punisher Showed Up In Captain America: The Winter Soldier

The gun-toting vigilante was rumored for the MCU far earlier than Netflix’s integration.

In Captain America: The Winter Soldier, Hydra’s forces are at one point curtailed by the sudden appearance of a yellow Penske truck, t-boning their pursuit vehicles in what seems like a random accident at first glance. When Director Joe Russo teased the truck driver’s identity, supposedly driven by someone with a “very specific skill set“, The Punisher’s name quickly surfaced. Sadly, nothing ultimately came of this cryptic tease, representing just another loose thread the Marvel Cinematic Universe was never able to follow up on. The Punisher has still yet to make an on-screen appearance in the MCU.

The Punisher has still yet to make an on-screen appearance in the MCU.

3. The Soul Stone Was In Wakanda’s Meteor

The mystical gem would explain much of Vibranium’s fantastic properties.

Yet another proposed location for the mysterious Soul Stone was within the massive meteor that gave Wakanda its trademark Vibranium deposit, the stone ultimately being responsible for the nation’s technological prowess. Considering the many magical properties of the mineral, from nigh-indestructibility to the growth of the heart-shaped herb, an Infinity Stone wouldn’t be an unreasonable explanation. This would’ve also explained Thanos’ invasion of Wakanda in the trailer of Avengers: Infinity War. It’s understandable why the MCU wouldn’t want to have so many gems on Earth alone, but Wakanda as the gem’s keeper would’ve made more narrative sense.

2. Alexander Pierce Was The Red Skull

Captain America’s old enemy almost made his surprise reappearance much sooner.

The mystery of the Red Skull’s whereabouts after being beamed away by the Tesseract in Captain America: The First Avenger was a hotly-debated topic for some time, with a leading theory beginning to prevail around the time of Captain America: The Winter Soldier‘s release. As an enigmatic villain affiliated with Hydra, Alexander Pierce turning out to be a mere persona of the Red Skull using another life-like mask to conceal his identity seemed almost too obvious not to be true. Alas, the Red Skull wouldn’t reappear until Avengers: Infinity War, and Pierce turned out to be a forgettable political villain.

1. Stan Lee Was Old Steve Rogers

A fan theory shockingly close to the truth.

Long before Avengers: Endgame hit theaters, rumors of the film’s focus on time travel breached the containment of Marvel’s story team. One popular theory purported that Stan Lee’s many cameos in MCU films were actually an old Steve Rogers, checking in on the timeline over the course of his retirement. While Captain America would indeed go on to travel back in time and age into an old man, Stan Lee was confirmed to be a Watcher in the Marvel Cinematic Universe thanks to Guardians of the Galaxy: Vol. 2.