Fanon/Film

Animated Films

 * The Lion King.
 * Many fans think Simba and Nala had a son, named Kopa, who was either then killed by Zira, or otherwise died, or is at least gone somewhere awaiting a fanfic plot that re-unites him with his lost family. A confusing example, as Kopa was a character in the semi- or non-canonical storybook The Lion King: Six New Adventures published between the 2 movies, but was then never mentioned in the 2nd film. This has been speculated to be due to grief or something, but it's more likely that he was just Ret Conned out of existence. It's thought that he, and not Kiara, was the cub pictured at the end of the original movie. It's also due to the cub's coloration at the end of the first movie (resembling Simba's at the beginning and all the lionesses are a lighter color).
 * It's required in fanfics that if Kiara and Kovu have a son, he be named Tanabi.
 * Considering the other Lion King movies aren't officially in the Disney Animated Canon (which doesn't necessarily mean anything to the Lion King universe), some fans just dismiss Kiara's existence completely and replace her with Kopa.
 * Nala was meant to have a younger brother named Mheetu but he was taken out of the final product. Fans often include him in fan-works, either as her unseen brother or her dead sibling.
 * The Princess and the Frog
 * Despite (or because of) the fact he's from a fictional country, many fans still throw Fan Wank fits over Prince Naveen's "real" ethnicity — namely, whether he was closer to Mediterranean or Middle Eastern and/or Indian on the sliding scale of Ambiguous Brownness. That is until some people picked up on a throwaway line in "Friends on the Other Side" ("You come from two long lines of royalty") and ran with it. The final conclusion? He's all of them.
 * There's also the matter of Tiana being outbid on the restaurant. It has generally become accepted amongst fans that the "other buyer" story was orchestrated by the mill's owners, either with them outright lying or with them getting someone to outbid Tiana's offer. While this does explain why Tiana conveniently is outbid the very day she tells the owners she's ready to purchase the place (and why no "other bidder" gets angry when Tiana has Louis scare them into selling), there's no official explanation for it in-movie.
 * How to Train Your Dragon fan fiction seems to have reached the consensus that a) Toothless is the Last of His Kind and b) Toothless is
 * Toothless's Last of His Kind status has pretty much been confirmed by both How to Train Your Dragon 2 and advance information on How to Train Your Dragon 3.
 * The Sword in the Stone. Many fans were so saddened by the heartbroken girl squirrel that several fanfics have emerged in which Merlin turns her into a human so she and Arthur can be together. Popular fan names include Hazel and Gwen. These stories are accepted by many as legitimate Canon just because they want so much for the poor little thing to have a happy ending.
 * Toy Story
 * The fandom has it that (SPOILERED for Rule 34)
 * Also, unless you ship Buzz/Woody or Woody/Dolly or Woody/Jessie,
 * Many fans theorize that Andy's mom was Jessie's original owner, Emily. There's no confirmation on this, but it would explain why she let her son keep a pair of toys that all but materialized in her house out of nowhere.
 * In Cars fan fiction, the name of the agency Finn and Holley work for is called C.H.R.O.M.E, which is derived from the video game adaption, but the agency's name is never actually stated in the film itself.

Live-Action Films

 * Various explanations for the inconsistencies of how time travel works between the three Terminator Movies are fanon. The Terminator movies (and the TV show, for example) never state how it works, just that it does.
 * Given that George Lucas himself has said that the only things he considers "official" Star Wars are the films and the Clone Wars cartoons, it could be argued that the entirety of the Star Wars Expanded Universe is nothing but Fanon. Some fans would argue with this point of view.
 * Wookieepedia, the Star Wars Wiki, has a fairly complete list of fanon elements that found their way into the official continuity, either as an intentional homage or due to the authors mistaking them for canon.
 * SuperShadow, a website that deals almost exclusively in bizarre fanon notions, whose webmaster alleges that he is a close personal friend of George Lucas. SuperShadow is generally avoided by Star Wars fans, and discussing SuperShadow at all in a serious forum will get you slapped. Many of these people can't tell if SuperShadow is run by an idiot, or is just an elaborate prank played on a community that's already rife with ridiculous fanon ideas....
 * A particularly irritating bit of fanon (covered in the blurb of this Darths and Droids strip) that many people still can't seem to understand is false is the idea that the "Balance of the Force" refers to the Balance Between Good and Evil and was reached when Anakin killed all but two of the Jedi (Obi-wan and Yoda) leaving the number of Jedi and Sith equal. This is especially weird/frustrating when you consider how many people use the Jedi not thinking this would cause most of them to die out as "evidence" for them being stupid/corrupt and/or the prequel trilogy being an Idiot Plot. Word of God has stated that "Balance of the Force" means some Jedi, no Sith, and that the previous Jedi order didn't need to die. (And this line of thinking doesn't make much sense, either: an equal number of Jedi and Sith [unless that number was zero] wouldn't engender balance in anything and just cause an unending and highly escalated war.) As once was said, a lot of fans miss the idea that the Dark Side isn't Yin. It is Sin.
 * There's also much simpler theory from Alkor: the imbalance was caused by "Light side - Dark Side" dichotomy itself and everyone contributing to it was a part of the problem - in which case, the prophecy was fulfilled as Anakin's life and deeds step by step resulted in both Jedi and Sith being near-exterminated (and discredited). Jedi didn't see why this bell will ring for them too - but the same people said "there's no Light and Dark Side, only the Force" and "Only a Sith deals in absolutes" and in their habitual hypocrisy didn't notice how it clashes with their other rhetoric.
 * There's also the idea that the midichlorians somehow create the Force. There's no indication of that in Canon, and according to Wookieepedia they are merely indicators of Force Sensitivity. There's even an in-universe theory establishing that the Force creates the midichlorians.
 * The Expanded Universe is full of them. First we have the theory that Luke lost his virginity to Leia right after the Battle of Yavin. Then there's the theory that Anakin is really Ben's father. Sticking to Mara, another theory is about Palpatine's relationship with Mara. Slash fans vary from Everyone Is Bi to attitudes toward homosexuality are as restrictive in the GFFA as they are in Christianity, despite the fact that Jaina thought nothing of Goran and Medrit. And despite Lucas saying the Jedi have sex, the mischaracterization of them as celibate continues to this day Moving away from sex, most fans believe that Luke was under the Dark Side's influence in the Dark Nest Trilogy.
 * Regarding homosexuality in the GFFA, Bioware caught hell for Juhani, whose article is still a mess from people arguing whether or not she was written as a lesbian. Stanley Woo, her writer at Bioware said unequivocally that the answer is YES.
 * And then we get Karen "Canderous Ordo in Drag" Traviss who settled at least part of the issue by stating that the Mandalorians don't give a shit.
 * Male Exile. How many times was Wookieepedia edited for that one?
 * Ditto with so much as acknowledging Revan could be played as a female. Even the mention of it caused flame wars for a while. Give me a nickel every time some fanboy screams "Revan can't be a girl, it's CANON" and force me to pay a dime back every time someone says "Exile's a chick. It's CANON," and I'd still have enough money for a five-star supper and gas money.
 * We don't know what kriff means, just that it is used emphatically. It is assumed it means "to have sexual intercourse with".
 * R2-D2 has such a potty mouth, fip-jing doot bippity. After all, C-3PO once said to R2, "Watch your mouth", and everything it says is bleeped.
 * The Big Lebowski: a popular theory among fans is that Donnie is in fact Walter's imaginary friend.
 * Which doesn't make sense, because the Dude also acknowledges him a few times during the movie. Unless he is both Walter and the Dude's imaginary friend. But if he was, Unless that was a dream sequence... And so was . The Stranger also refers to Donny, meaning he's also an imaginary friend. And who is bowling with them the whole time?
 * The Jesus also acknowledges Donny during the movie too.
 * As does Gary, the bartender at the bowling alley.
 * The Usual Suspects: There are a number of fan theories that identify Keyser Soze as any member of the cast you care to name. In the director's commentary, the filmmakers express puzzlement over this phenomenon, saying they felt the end is pretty clear.
 * In The Film of the Book of Prince Caspian, a geeky boy attempts to flirt with Susan at the train station in the first few minutes of the film. A small group of fans have grown attached to him, and christened him Warren.
 * Figwit the sexy elf from The Fellowship of the Ring was noticed by fangirls and anyone else who got bored during the Council of Elrond scene; he was adopted by the fandom and given his name, and when he reappeared in RotK, there was much squealing and choking on popcorn. Incidentally, he's played by Bret McKenzie of Flight of the Conchords.
 * Event Horizon is said by some fans to be set in the Warhammer 40,000 universe.
 * Ditto for The Chronicles of Riddick. It IS extremely easy and quite possible to argue that it takes place sometime in the Dark Age of Technology. In fact, the events of the film line up quite perfectly with much or all that is known about the Warp. While the film makers may or may not have intended it, it is in fact perfectly reasonable to say that Event Horizon is the first ever WH40K movie.
 * Fight Club
 * A surprisingly large number of people sincerely believe that the name of Edward Norton's character is Jack. In fact - and this is lampshaded in the film - his true name is
 * In the script and behind the scenes they did use the name Jack, though.
 * Another popular theory is that Calvin and Hobbes is the prequel to Fight Club, with the Narrator being an older Calvin, Marla as Susie, Bob being an older Moe trying to be The Atoner and
 * The fandom for Inception has unanimously decided that Eames' totem is a poker chip. This is fleetingly implied in the film but never explicitly stated.
 * Michael Myers, the antagonist of Halloween
 * Another of his fan films depicts Freddy Krueger  This contradicts Freddy vs. Jason vs. Ash and its sequel, but these are an alternate sequel to Freddy vs. Jason than Jason X, which couldn't take place after Freddy vs. Jason vs. Ash 2: Nightmare Warriors because
 * In The Boondock Saints fanon, it's generally agreed that Connor is the older twin.
 * High School Musical fic
 * If Chad is not dating Taylor, he's dating Ryan 99% of the time. Probably has something to do with the sexy baseball scene in the second movie...
 * Sharpay often has a cutesy nickname that her mother calls her by, to go with Ryan's "Ducky".
 * Sarah's mother in Labyrinth is usually referred to as either "Karen" or "Irene". No one seems to know for sure what her actual name is.
 * It's a popular theory among Quentin Tarantino fans that at least some of the events of Pulp Fiction occur on the same day as the bank heist in Reservoir Dogs; in particular, the fact that no cops are around to stop Jules and Vincent while they're driving a car covered in blood in the middle of a busy street during broad daylight is because they're occupied with the heist and its disastrous aftermath.
 * Many viewers of Avatar believe