Most fan-made theories can be aptly categorised in one of the following ways - 'fever dream lunacy', 'honking stupidity', 'desperate self-projection', 'Wash might've survived' and, of course 'unexpected flips in sexual orientation'. Fortunately, there are some interpretations worth bearing in mind - some ideas that are so out of the box, so revelatory and so downright brilliant that they alone solve many of a movie's issues, wrapping up nagging questions and presenting the piece in a new and utterly intriguing light.
This list looks at 25 of the very best fan-made theories, from the 'so mad it just might work' to the 'dude must've stolen a script'. Prepare to look at the likes of James Bond and the world of Quentin Tarantino in a whole new light. Begin!
25. Labyrinth (1986)
The fan theory: Labyrinth is a metaphor for a girl struggling with the onset of puberty.
Why it's mind-blowing: Think about it: the whole thing is about a young girl taking responsibility and going in search of a child. The labyrinth around her is constantly changing, and challenging her along the way, à la a teenage body. And then there's the involvement of Jareth, with his extremely pronounced codpiece. Ahem.
24. Spider-Man (2002)
The fan theory: Spider-Man is also about Peter Parker's attempts to cope with the stresses and strains of teenage life.
Why it's mind-blowing: Overnight Peters body takes a drastic change for the adult, while he starts discovering white fluid all over his wrists. Sorry to put it bluntly, but it's a bit obvious.
23. Jurassic World (2015)
The fan theory: The Indominus Rex is hyper-intelligent, enjoying toying with the various humans who gets in its way, killing for the fun of it, and letting loose pterodactyls to distract the helicopter that's chasing it. Could it be...part human?
Why it's mind-blowing: The dino is famed for being a genetic cocktail, with part chameleon, T-Rex, velociraptor, as well as cuttlefish and treefrogs. Maybe the morally-dubious scientists sneakily chucked some human DNA in there too...you know, to make it even more of a tourist attraction. It's above-average intelligence means it's cleverer than a velociraptor, so it's definitely a possibility...
22. Fight Club (1999)
The fan theory: The narrator and Tyler are a distorted version of Calvin and Hobbes, the cartoon tiger-boy duo.
Why it's mind-blowing: Having been forced to suppress his imaginary childhood friend by the necessities of growing up, Calvin's overactive imagination comes back into play in big way when he finds himself stuck in a rut in adult life. It's a stretch, but we like it all the same.
21. Reservoir Dogs (1992)
The fan theory: The bank heist takes place on the same day that Jules and Vincent play out their story in Pulp Fiction.
Why it's mind-blowing: It would explain why the hitmen are able to drive a blood-soaked car through a busy city without encountering any police-based trouble. The boys in blue are clearly busy elsewhere.
20. Toy Story (1995)
The fan theory: Andy's parents are in the middle of a divorce when the film is taking place.
Why it's mind-blowing: It actually makes a lot of sense, since we never see hide nor hair of Andy's dad, and the whole story is driven by his mum's need to downsize to a smaller house. Then there's the fact that Andy is an extremely introverted kid. It all adds up!
19. Blade Runner (1982)
The fan theory: Not only is Deckard a Replicant, but he is a Replicant implanted with the memories of a former Blade Runner. Detective Gaff to be precise.
Why it's mind-blowing: It would explain the weird connection that exists between the two, but also Gaff's obvious resentment of Deckard. Could it be that his limp put him out of service, only for Deckard to step in as his replacement? It's possible...
18. Twilight (2008 2012)
The fan theory: Bella isn't actually human at all - she's part werewolf.
Why it's mind-blowing: It would be a much neater way of explaining why none of the other vampires are capable of reading her mind, or why Edward was capable of getting her pregnant when vampires and humans are seemingly unable to procreate. Werewolves throw vampire powers out of whack, remember?
17. The Matrix (1999 - 2003)
The fan theory: Neo is actually a machine, with the real world of Zion turning out to be just another level of human-created simulation, designed to keep technological advances in check.
Why it's mind-blowing: It would have resulted in the big reveal that the Matrix was actually a human-created way of keeping advancing technology under control. Whoa, dude!
16. No Country For Old Men (2007)
The fan theory: Anton Chigurh is the Angel of Death, sent by an angry, Old Testament God to wreak vengeance upon the drug trade.
Why it's mind-blowing: It would explain Chigurh's total indifference to the fate of his prey. Although not why he takes such pleasure in messing with that gas station attendant.
15. Inglourious Basterds (2008)
The fan theory: The rest of Tarantino's films follow on from this alternate version of history. Having WW2 ended in a movie theatre explains why all his characters are so pop-culture savvy.
Why it's mind-blowing: We already know Tarantino likes to link all his movies together - this just expands that way of thinking a little further!
14. Inglourious Basterds #2 (2008)
The fan theory: Inglorious Basterds is actually a movie-verse film directed by Lee Donowitz (a distant relative of the Bear Jew), lionizing the involvement of his forebear.
Why it's mind-blowing: It would make sense given Donowitz's success as a war-movie auteur with Coming Home In A Bodybag.
13. Kill Bill Vol. 1 (2003)
The fan theory: Kill Bill is a movie within the Tarantino world, as is From Dusk Till Dawn - which would explain their hyper-violent aesthetic, even by Tarantino's standards.
Why it's mind-blowing: Tarantino himself has said that this is as true. Extrapolating things further, one could read Kill Bill as Fox Force Five: The Movie with Mia Wallace in the leading role.
12. Taxi Driver (1976)
The fan theory: Travis Bickle dies at the end of the film, and that weirdly optimistic final reel is actually taking place in the mind of a dying man.
Why it's mind-blowing: It goes a long way to explaining the unusually happy ending provided by such an unremittingly bleak film.
11. Kill Bill Vol. 2 (2004)
The fan theory: When the end credits roll, all the characters whom we know to be dead have their names crossed out. Darryl Hannah merely had her eye plucked out, so she gets a question mark. But Bill? Nothing at all. Ipso facto, the Bride doesn't actually kill him.
Why it's mind-blowing: It would suggest that Bill was playing dead. After all, it's made clear on several occasions that only Pai Mei has successfully mastered the five point palm exploding heart technique.
10. Signs (2002)
The fan theory: Those marauding creatures aren't aliens at all. They're demons! So now you know.
Why it's mind-blowing: It takes what was a slightly laughable ending, and makes it far more credible. The reason the water from a priest's house stops them dead in their tracks? It's holy water!
9. The Avengers (2012)
The fan theory: The entire outcome of the film follows Loki's plan to the letter, with securing a return to Asgard proving to be his goal all along.
Why it's mind-blowing: It could be an excellently subtle set-up for Thor 2. Why would Loki be so keen to return to his homeland in the first place? Could it possibly have anything to do with the Infinity Gauntlet we caught a glimpse of in the first film?
8. Forrest Gump (1994)
The fan theory: Jenny's son, who is presented to Forrest as his own offspring at the movie's conclusion, isn't really his son at all.
Why it's mind-blowing: It tallies with what we know about Jenny (she gets around a bit), and adds a more bittersweet sheen to the movie's conventionally happy ending.
7. My Neighbour Totoro (1988)
The Fan Theory: Cuddly woodland guardian Totoro is not the loveable critter you thought he was. He's actually the God of Death.
Why Its Mind-Blowing: Satsuki's search for her sister Mei is actually fruitless. The fact that both of them encounter Totoro means that, actually, both of them are dead. Makes you want to put that Totoro cuddly toy at the back of the cupboard, doesn't it?
6. Pulp Fiction (1994)
The fan theory: The briefcase contains Marsellus Wallace's soul.
Why it's mind-blowing: Legend has it that the Devil removes a person's soul through the back of their head, where Marsellus has a plaster. The combination to the briefcase is 666. The contents glow with ethereal beauty. How obvious do you want to make it?
5. The Shining #1 (1980)
The fan theory: Jack Torrance represents white oppression of the Native Americans. And the location of the hotel is just the start of it.
Why it's mind-blowing: Not only does the hotel have a Navajo wall hanging (that Jack repeatedly throws a ball at), his wife can be seen wearing a tepee jacket. Jack also starts banging on about white man's burden and the date of that creepy photograph is July 4th. A coincidence? We think not.
4. The Shining #2 (1980)
The fan theory: Stanley Kubrick helped fake the moon landings, and The Shining contains several coded admissions. Didn't you notice Danny's jumper? Keep up, keep up.
Why it's mind-blowing: As fan-theories go, it's pretty out there. Although when it comes to The Shining, people don't tend to hold back on their theorising. Check out Room 237 for further details!
3. Ferris Buellers Day Off (1986)
The fan theory: The entire film takes place in Cameron's head, with Ferris created by his buddy as the polar opposite of his own depressive personality.
Why it's mind-blowing: It explains some of the movie's more fantastical elements (the whole city of Chicago rallying around Ferris), and fits in nicely with the movie's ending in which Cameron decides he must stand up for himself more and finally has no further use for Ferris.
2. Star Wars (1977 2005)
The fan theory: Chewbacca and R2-D2 are secret Rebel agents, using their knowledge of Anakin's transformation and the rise of the Galactic Empire, rather than inexplicably forgetting it.
Why it's mind-blowing: It sorts out some of the plot holes established by the creation of the prequel series, while also adding some welcome gravitas to the two fan favourites. We much prefer this to C3P0 getting a convenient memory wipe.
1. Skyfall (2012)
The fan theory: James Bond isn't a man but rather a codename, passed on from one MI6 agent after the other over the years.
Why it's mind-blowing: It neatly explains away why various different Bonds look and behave differently, while supporting characters (M, for example) continue to age before the audience's eyes.