The word "theory" calls to mind all those boring science classes and terrifying exams that we had to endure when we were in school. But there’s a new definition for "theory" that gets the geek in you racing to meet it, learn more about it, and share it all over social media. This theory even entices you to enter into heated keyboard wars. We're talking about fan-based movie and TV theories.

Remember all those times you were frightened to even log in to your social accounts for fear of coming across Game of Thrones gossip? Or even a little something from your other favorite shows that you simply did not want to hear about ahead of time?

Your situation with this article is simple: It is the mother of all movie spoilers! Every point we cover below are confirmed (or comes near enough to) fan theories in the DC and Marvel Comics movie universes. Some of these theories you will need to wait to see if they ring true, and others you might be on the verge of confirming yourself. So enter at your own risk. This train has started and it’s going to be a bumpy ride.

25 Reason Behind The Greatness

via: comicbook.com

You can't start a superhero-related article without making mention of the excellent Stan Lee. Have you ever wondered why precisely he performs cameos in several superhero movies?

He’s appeared in so many these past 20 years, we’ve lost count.

Except for that Fantastic Four flick, his appearances have got fans talking. Stan Lee himself refuted the rumors, but that only further spread the fires of speculation. At last, in Guardians of the Galaxy Vol 2., we see him in a post-credits scene narrating his adventures to the Watchers. Fans came to learn from James Gunn himself (in a Radio Times interview) that Stan’s a Watcher Informant, in keeping with Marvel’s multiverse-magic. We’ll probably know soon in future, but it’s official canon now.

24 Wolverine’s End Was Revealed In 2013

via: collider.com

The Wolverine! Just hearing that name conjures action-hero value on a par with Batman, or even Thanos for that matter. The 2013 movie that revolved around this outstanding X-Man gave away Logan’s eventual fate, as seen in the 2017 movie. In the interim, fans were going gaga trying to root out confirmations for their theories concerning Logan’s final moments.

Movie Pilot has credited the ideal fan theory to @moegonzales3 for linking the dots hinted by Yukio, a mutant psychic, who told Logan, “I see you on your back, there's [redacted] everywhere. You're holding your own heart in your hand.” The prophecy comes true in the 2017 movie, and Logan perishes holding the hand of daughter X-23. James Mangold confirmed that he intended for the link to be integrated into the storyline in exactly this fashion.

23 The Quantum Theory: From Ant-Man To Doctor Strange

via: marvelcinematicuniverse.wikia.com

Universes can mean many things to a geek and other things to a nerd. In this particular case, we are referring to two of the MCU’s big-hit movies, namely Ant-Man and Doctor Strange. Both have given us a plethora of scientific mysteries that drew their inspiration from the real world.

This is particularly true of the Quantum Realm, a concept ideally given center-stage in both movies.

Whereas Ant-Man gave us some laughs as well as action, Doctor Strange took us through a more serious storyline. Ever since fans were introduced to this realm in Ant, they have theorized its comeback in future MCU movies, which is exactly what happened in Strange when the Ancient One took the good doctor on an inter-dimensional tour, and one of the stops was the Quantum Realm.

22 The End Of Asgard

via: YouTube.com | Mr. Spoiler

Theories abounded concerning the finale of Thor: Ragnarok. Not one, but several speculations were debated about online. Like the time fans said Loki might have a hand in Hela’s release. After learning of Odin on Earth, fans speculated that Doctor Strange might get involved. However, the most powerful theory that came true actually occurred way back, following the release of Avengers: Age of Ultron.

We saw how Heimdall hallucinated the end of Asgard, sharing also that Thor would be responsible for it one way or another. The ongoing theory was that Asgard will be no more by the time the filmmakers released the third Thor installment. Granted, fans did not foresee the exact manner in which Asgard would burn, but the fact that it was destroyed in the second Thor movie speaks volumes. This is not at all how Asgard met its end in the Avengers comic books.

21 The Final Infinity Stone

via: marvelcinematicuniverse.wikia.com

We came across a curious theory involving the former Bifrost Bridge guard. When you think about it, the whole Marvel storyline seems to be gearing up toward encountering the powerful weapons/tools called the Infinity Stones. CBR has listed them as Space (Tesseract), Mind (Loki’s Scepter), Reality (Aether), Power (the Orb), and Time (Eye of Agamotto; Nexus).

The Soul Stone is all that remains, and fans got a peek in a vision sequence in Guardians of the Galaxy.

Fans found the same stone in Heimdall’s breastplate in Thor: The Dark World, leading them to believe that this is the power that Loki mentioned was exclusive to Heimdall. It apparently helps him keep vigil over the nine realms, and Heimdall himself told Thor that he can gaze into ten trillion souls with it.

20 Nick Fury’s Secret Power

via: slashfilm.com

There’s something about the leader of S.H.I.E.L.D. that remains cloaked in mystery... until a fan theory broke that box wide open. Nick Fury still has two eyes, but one of them’s the third. Not only did he assemble the Avengers before an imminent NY alien invasion, he also approved a program that resurrects the deceased. He did that only a short while before one of his best agents fell in the line of duty.

There are too many timely coincidences for fans to assume that Nick is strictly strategizing. Take when he showed up at Hawkeye’s farmhouse in Avengers: Age of Ultron. Nothing adds up to how he could have planned to arrive hours after the Avengers did. Despite being away from S.H.I.E.L.D. for a while, he knows an awful lot of classified data concerning Ultron.

19 Spidey Makes An Appearance

via: YouTube.com | Hybrid Network

Speaking of Starks, we call your attention to Iron Man 2, not to share some bewildering theory about Tony but rather to reveal a little something extra about Spidey. We have witnessed the brotherly bonding between Peter Parker and Tony Stark, so this point comes as a welcome surprise. We saw Spider-Man, technically a Marvel legend in his own right, enter the Avengers fray only as recently as Captain America: Civil War.

Marvel had other plans to progress the Spider-Man franchise up to that moment.

Spider-Man actually made an indirect debut in Iron Man 2, adding fan-flavor to the bromance that he attains with long-time boss, mentor, and eventually Avenger-teammate, Tony Stark. The boy in the Iron Man mask in that movie…? That was Peter, according to Tom Holland. It’s always fun to see some meaningful connections in a universe as vast as Marvel’s.

18 The Real Hydra

via: comicbook.com

Captain America: The Winter Soldier gave us Hydra, with nothing much shown of them in preceding MCU movies. Fan theories beg to differ. Word on the grapevine is that Iron Man gave us an unforgettable peek into the Hydra we all know and hate. Remember Obadiah Stane? He made it up the corporate chain, awaiting only the demise of Howard Stark at Bucky’s hands to take over Stark Enterprises.

Tony Stark got in the way of all that, repressing Obadiah’s influence at Stark Enterprises.

Tony has always been at the company, in the weapons-tech labs away from office politics. Stane planned to ‘accidentally’ end him when his ways got too wild for the company to cover. This was around the ‘Jericho missile’ time of events. Obadiah’s words in relation to that terrifying weapon hinted more about balancing power in the name of a secret organization.

17 Mischief Managed... Signed, Loki

via: fanpop.com

For a god infamous for scheming, trickery, guile, and manipulation on a diabolical scale, Loki proved rather placid in The Avengers. He makes a scene, gets captured, is temporarily jailed in a helicarrier… It soon becomes obvious that he planned to release The Hulk to ensure that the Avengers team up.

Intent on ruling Asgard, and uncaring about all things Earth-related, Loki suddenly seemed awfully vested in the future of the human race. With his scepter, he deceived Selvig into adding a failsafe to the portal device that the Avengers later rely upon. Following this, the team sends the Tesseract with Loki and Thor back up to Asgard, where resides one of the Infinity Stones and a very special gauntlet. Loki is ideally placed to perform a swift takeover with these objects, adding credence to the theory that he was fooling the Avengers from the start.

16 Aquaman Meets Superman

via: mashable.com

This might sound rather out of the blue, but we assure you we haven’t lost our marbles; yet. Canon-wise, we do not see these two heavyweight-characters meeting until Justice League. The time when all the big-hitters are brought together to counter an alien threat, we received an interesting line from Aquaman as Superman came to the fore.

The King of the Oceans had apparently met the Man of Steel.

The Man Of Steel scene in question aptly takes place in a watery environment, and fans have pointed out that Aquaman, though not on-screen, was probably in the water during a certain chance encounter with Clark Kent after he was blown clear off an oil rig and into the ocean. Snyder confirmed as much to DC All Access.

15 Groot Is Possibly Immortal

via: YouTube.com | FRESH Movie Trailers

Guardians Of The Galaxy gave us one of the best characters ever, namely Groot. For a while, Baby Groot in Vol.2 was thought to be the original character growing from scratch. Canon says Groot can regenerate into his grown-up self even from a tiny preserved sliver of his original body, granting him a sort of immortality. But James Gunn tweeted, "First Groot is [deceased]. Baby Groot is his son." This statement is quite open-ended in light of one fan-theory: Groot came from Yggdrasil, aka the World Tree of Norse Mythology.

There is a subtle throwback to this possibility in Captain America: The First Avenger. During his Tesseract-hunt, the Red Skull notes upon looking at a carving, “Yggdrasil, the world tree. Guardian of wisdom and fate also.” Seemingly disjointed dialogue… Perhaps a Marvel hint?

14 Valkyrie Has A Girlfriend

via: YouTube..com | Mr. Spoiler

Between Wonder Woman’s female empowerment and Black Panther’s power, societal norms are bending, changing, and one could even say evolving. We believe similar ideals need to apply to the LGBT community, and we already have a poster girl in the superhero universe who can best portray that segment.

Enter Valkyrie.

A certain scene in Thor: Ragnarok revealed a female Asgardian soldier sacrificing herself to save Valkyrie from Hela. It was no random act of compassion because the look the two women shared before one of them fell spoke volumes. The actress who played Valkyrie, Tessa Thomson, has confirmed that her character is indeed bi. She even pointed our attention to the deleted scene from the movie. And now fans await with bated breath for future Marvel films, where Valkyrie has purportedly been given a light of her own.

13 Chief In Wonder Woman Is... A Demi-God

via: dcextendeduniverse.wikia.com

It’s splendid to realize that Wonder Woman got the whole inclusion train rolling. No longer are the Amazons portrayed as a colony of white women. The image has been re-made to include warrior-women from diverse racial backgrounds; even Gal Gadot is Israeli. Then along came Black Panther, adding further promising changes to the future of superhero cinema.

In a story set during World War I, fans are doubly treated to historical storylines and a set of characters who bring mystery to their roles in Wonder Woman. One such is the Native-American called Chief, who briefly accompanies Diana on her mission. Chief actually introduced himself in his native tongue as the Blackfoot demi-god Napi. Granted, neither Warner Bros. nor Patty Jenkins has confirmed this; yet. The meager screen-space allotted to Chief could probably explain why we weren’t told more about his ancient roots.

12 The Red Skull... He Lives!

via: marvelcinematicuniverse.wikia.com

Touted to be one of the most admired Marvel villains around, the Red Skull has given us thrills and chills like only a handful of other fictional bad guys we know. His end seemingly took place in Captain America: The First Avenger, but fans have since speculated that his passing may not be set in stone. After all, this is one of the most sought-after villains in the MCU. The Red Skull’s end-scene portrayed him being disintegrated by the Tesseract.

A bright blue flash and he disappears into a portal.

Pay attention: there was no hole in the top of the plane after the light-show. It was, therefore, a portal, not a simple energy beam. This is further supported by the fact that the Tesseract is known to teleport people. Perhaps the Red Skull took a doorway to another place.

11 Hydra Made The Avengers

via: blogdesuperheroes.es

Fans found a wealth of lore in Captain America: The Winter Soldier, including Hydra’s ongoing plans to track individuals with super-powers. With near efficiency, they even kept an eye on Stephen Strange’s movements, before he went to Kamar-Taj. Hydra was also onto Captain America in the 50s, with the express aim of ending him before he became a liability, a detail they applied to Iron Man too.

The theory that Hydra covertly managed S.H.I.E.L.D. to bring all the heroes together to form the Avengers took wing.

Even in the short-film direct-to-video Marvel One-Shots, we saw Jasper Sitwell (‘The Consultant’) working on assembling the Avengers; Sitwell was a confirmed Hydra double-agent. The secret society even shook hands with a demi-god. They brought Loki on board and planned the Chitauri Invasion, so the Avengers will happen.

10 The Chitauri Invasion Was A Conspiracy

via: marvelcinematicuniverse.wikia.com

Don’t you feel the Chitauri Invasion was a bit… convenient? What we mean is, didn’t it end like it was doomed to fail from the get-go? There was no attempt at hiding their invasion! Loki cracked open a mega-portal smack in the middle of New York, where heavy resistance would come much sooner than if the invaders took their time, came in slow from the countryside, and carried out a decisive conquest.

S.H.I.E.L.D. was already prepping to nuke NY, and we know that Hydra had a hand in several pies, including placing double-agents inside the Supreme Headquarters who schemed the guaranteed end of the Avengers. In short, the invasion was a conspiracy to bring the powerful Avengers together in one place so they could be nuked under the excuse that aliens were about to take over.

via: slashfilm.com

The DC universe gave us an insightful look into how carefully Zod planned to use Superman: inside Kal El is the Kryptonian genetic codex of his race. Amidst battles to take over the Earth, Zod tries to get Superman to help him re-create a new Krypton. But Zod knew that that particular conversation required more than tea and cake, so he puts Superman through an induced nightmare where he drowns in skulls.

Zod emotionally torments Kal; "Look at how many people you have [eliminated], Kryptonian."

When Dawn Of Justice released, fans drew a connection to this scene and the one where Superman saved hundreds of lives in a Day of the Dead celebration. The celebrants decked in the day’s skull-based paintwork and costume reach out to pay Superman homage, a symbolic juxtaposition to what Zod put him through in Steel.

8 Superman’s Super-Guilt Syndrome

via: source.superherostuff.com

On a related topic, we have another Zack Snyder confirmation that reveals how intently he desired to reveal the human demise toll in superhero movies. The skulls were symbolic of this and took viewers and fans into Superman’s psyche where he was weighed down by the many guilt-ridden moments where people actually perished on his watch and he couldn’t do anything about it. Zack mentioned how more than five thousand people perished during the events of Man Of Steel.

Batman vs. Superman: Dawn Of Justice showcased how Superman saved a girl from a factory fire and was well-received by revelers wearing Day of the Dead celebration masks and outfits. The skulls were an obvious throwback to the guilt inside Superman that has probably been eating at him for years. This emotion-packed fan theory holds plenty of substance, and it’s a theory that’s been confirmed.

7 Whatever Happened To Pepper Potts

via: myconfinedspace.com

Iron Man 3 gave us action and revelation, not the least among which was the end of Pepper Potts, Tony Stark’s on-again-off-again who’s been through heck and high water with him. We don’t see her in any of the eight MCU movies that followed. Tony never revealed what happened to her, except by saying "She’s busy" every time someone asks. A certain scene in Captain America: Civil War gave us a huge hint as to Pepper’s whereabouts.

Tony has an expression on his face that could only be described as despairing.

While the tech-billionaire’s assistant shares that Potts canceled, a sturdier theory has started to hold sway. Pepper was part of Tony’s Extremis experiment, and might well have perished at some time because of it. She seems to be back by Spider-Man: Homecoming, however.

6 Thanos Will Revive Villains With The Infinity Stones

via: Reddit.com | Jordan Chez

The bad guys have it bad in the MCU universe. Fans uphold that they are finished off too soon in the storyline. Study what happened to Baron Von Strucker, Crossbones, Red Skull, Malekith, Iron Monger… and you’ll start to see a pattern. Marvel isn’t moronic, they have proven to hide hints and hidden meanings in several seemingly random or underplayed scenes. With Avengers: Infinity War on the horizon, we’re probably looking at a major villainous comeback courtesy of Thanos and his use of the Infinity Stones.

Armed with the gauntlet he stole from Asgard, he can work the Soul Stone to bring people back and change reality itself using the Reality Stone. It was hard enough to eliminate each villain when they were solo, but now that Thanos is probably forming a mega-club of evil-doers, chances are the Avengers might be strong-armed into submission.