Continuity Snarl



""Thanagar's champion, Hawkman can talk to birds. He also can't talk to birds. Sometimes, he can't even speak normally at all! Even if he could talk normally, or to birds, there are no birds on Thanagar, because it does not exist. Hawkman was sent here to study Earthly police methods, because Thanagar's own methods suck!""

- Kirk Kimball, of Dial B for Blog

"Continuity gets harder and harder to maintain the more stuff you write. At some point you just need to chuck it all in and accept the fact that in your universe Napoleon Bonaparte was a video game programmer and an Egyptian Pharaoh."

- David Morgan-Mar

A Shared Universe can become a very confusing place, and the longer they exist, the more confusing they can become. As new creators come on board and take over, continuity eventually gets tangled, convoluted, and increasingly difficult to pick through. Sometimes, it gets to the point that not even the fans who write Wikipedia articles understand what is and isn't in Canon.

It goes something like this: in the beginning, The Universe is created, and it's a blank slate. Everything's new; as such, the creators can do whatever they want to do, create whatever they want to create, throw everything in and have fun doing so. Whatever works, works and whatever doesn't, doesn't. So far, so good.

However, the whole idea of a Shared Universe is that different creative teams will eventually take over. Sometimes Writer A of Title A will leave and Writer B will take over, while at other times Writer A's character will guest star or make a cameo appearance in Writers B's title. People being people, those different creators will have their own ideas. They'll have different ideas about what the 'verse should be, about what has worked and what hasn't, what might work and what doesn't.

The new creative team will also want to make their distinct mark on the 'verse and their readership; as such, they'll have their own things that they want to add, things they disapprove of and want to remove or ignore.

Things that were previously essential may become irrelevant to the new team, and different character traits and events may be emphasized or ignored. They change things.

When another creative team comes along, they'll change things even more; they may even completely override the changes made by the previous team to include things that they want to see or to reassert a previous status quo. Unfortunately, sometimes what they regard as being fundamental to the original continuity was never even there to begin with!

The longer that this goes on and as more teams take over, the more chance there is of a Continuity Snarl. The more Retcons are made, Reset Buttons pressed, and the more the 'verse enters into a Dork Age.

There is also a bigger chance of certain things simply being forgotten and overlooked (and then possibly rediscovered and revived). As the process continues, more things become confused, convoluted and impenetrable. Weird inconsistencies and gratuitous retcons proliferate. Drastic changes opening up dozens of potentially fascinating story-lines are introduced... and then promptly forgotten about and left hanging (or immediately reverted) by another new team, which goes on to do something completely different.

And add to this the problems caused by Comic Book Time, it gets to the point that trying to keep things straight becomes a nightmare.

And that's just if there's only one main work in the Shared Universe to begin with—if you bring together many different characters and storylines set in the same universe and cross them over with each other, you have many different continuities going on at once. Trying to keep everything straight between them can be an exercise in complete madness, as the continuity between them is completely tangled up and near-impossible for anyone to unpick.

Unfortunate, if you have a fan-base which likes everything arranged in a neat, tidy little pattern and isn't shy about voicing their opinion when this isn't the case.

This is particularly a problem for comic books, especially in the DC Universe and the Marvel Universe, which have the long-running and tangled continuities of many a character to keep straight. Long-running TV franchises can also suffer from Continuity Snarls—the Doctor Who and Star Trek universes have gotten especially snarled over time (although the former can easily Hand Wave this away because it's about time travel).

A Continuity Snarl can result in Continuity Lock Out for readers, especially newcomers, as it becomes increasingly difficult to keep track of what's happening in the 'verse without a Masters Degree in Continuity Studies. Creators often resort to the Crisis Crossover to try and untangle the snarl they've made for themselves—unfortunately, this can just as easily become Continuity Porn, which more often than not just makes things worse. Can lead to a plain ol' Plot Hole.

When Canon becomes too involved and self-contradictory, it starts denying new writers "room to move." When writers disagree strongly with what previous writers before them have added to the mix and are overly keen on using continuity to get rid of them (or attack the other writer), then the snarl may come from the writers being Armed with Canon. If worse comes to worst, the writers may simply perform a Continuity Reboot, discarding the old continuity completely and starting over from scratch. (Everything you read or watched before? It never happened! You imagined it! Either that, or it was All Just a Dream.)

Every once in a while, the writer may just give up trying to fix everything and say, "Okay, it happened but not in every detail." Continuity Drift is when a Retcon sloooowly happens over a period of time.

Eric Burns of Websnark did a rant about it here.

See Armed with Canon, Comic Book Time, and Author's Saving Throw for common causes, may result in Continuity Lock Out, Continuity Porn, Tangled Family Tree, and Timey-Wimey Ball.

Anime and Manga

 * Dragon Ball, due to the filler episodes that are contradicted later (like Goku's pod being destroyed by Piccolo, only to be used later by Capsule Corp.) and the Non-Serial Movies that are still referenced later, but can't possibly fit into the show's timeline. (Gohan meets the dragon he rescues in Movie 3, but how could the Goku stop the Tree of Might from destroying Earth when Goku's either dead, fighting Nappa and Vegeta, in a hospital recovering, or en route to Namek? And if this is Garlic Jr. from Movie 1 who's pouring the Black Water Mist, then why did no-one recognise Gohan near the beginning of Z?) This leads to some glaring problems, like a character who was dead being seen in a bar drinking.
 * Despite mostly having only one writer, the classic Astro Boy series turned into a first class continuity snarl towards the end. See, what happened was that in the final episode of the original anime, Astro died performing a Heroic Sacrifice to deliver a device into the center of the sun to stop it from dying. Shortly after the anime ended, Osamu Tezuka began a new Astro Boy story as a newspaper strip in the Sankei Newspaper, which featured Astro's melted carcass being recovered by time-traveling aliens and brought back to life before winding up trapped in the distant past (the readers' present). Because Astro had never died in the manga, however, when the collected edition came out Tezuka redid the first chapter that involved Astro, alive and well getting thrown back in time when the alien timeship crashes on Earth instead. Tezuka then produced three more different, contradictory stories of Astro's future in various publications: a pilot for a second Astro Boy series that never got off the ground which also takes place after the end of the anime where Astro is found by a completely different race of time traveling aliens, upgraded into a new body with time travel capabilities and sent back to Earth to find the era he came from; A one-shot nostalgia piece in a men's magazine, yet another followup to the anime where Astro is resurrected by Sufficiently Advanced Aliens and taken to a planet millions of light years from Earth from which he may never return, so Ochanomizu and the rest of the Ministry Of Science staff create a replacement, who turns out to be a lazy sex maniac because he was designed to be more "Human"; and finally, "The End Of Astroboy", which doesn't mention his death and simply has him in a display case in a robot museum due to being supplanted by more advanced robots and then freed by some human rebels to help them fight against said robots who have taken over the world.
 * Pokémon has some of these, particularly concerning Jessie, James, and Meowth. This can overlap with Multiple Choice Past.
 * Like Digimon below, Slayers has clearly stated Alternate Continuity, and it's actually a bit milder here—the different continuities begin to form after the stories that compromise the first eight books, or the first two seasons of the anime, both of which are similar enough to avoid too much confusion. It's...still complicated:
 * In the novels, Lina actually meets Amelia's father, Prince Phil, and gets involved with his family feud before the series proper—the story of the first Slayers Special novel was transferred into the middle of the anime's first season: the same plot occurs, but Lina actually meets Amelia, and it goes from there. Also, the Atlas City story occured right after the very first fight with Shabranigdo, but the anime cuts to the aformentioned family feud, and the Atlas City story occurs during the second season. This makes little sense in context because in both the first book and the first episode, Lina is on her way to the city. Finally, Amelia appears after the battle with Copy Rezo in the novels, appearing in another Saillune royal family plot that was also implemented in the second anime season. Because she joins Lina earlier in the anime, she is with them during the Copy Rezo fight, and also meets Zelgadis earlier on.
 * For the anime, there's three more seasons of original stories (and apparently, the third season was disliked by the creator of the novel series). It gets more troublesome when one realizes that the fourth and fifth seasons came eleven years after the third, and the third season overall may be up for an official Canon Discontinuity by Hajime Kanzaka because of the aformentioned backlash.
 * The remaining seven novels remove Zelgadis and Amelia and replace them with Luke and Millina, and from there comes its own story.
 * Before he appears again in the fifth book, Zelgadis actually meets Xellos before the others do, hence why he knows of him when he appears. This is accounted in a side story.
 * There are a bunch of manga series that are their own sets of continuity. The most notable is the Hotter and Sexier universe of The Hourglass of Falces, in which all six protagonists (Lina, Gourry, Amelia, Zelgadiss, Luke, and Millina) are together. Naturally, the latter four never met one another at any time, and it would probably be impossible, given that Fans outside of Japan who are unaware of the second set of novels (as only the first eight were translated) probably don't know who Luke and Millina are.
 * The radio dramas are also rather bad at this. The worst case is the Slayers Premium radio drama based on the short Non-Serial Movie: because of the presence of Gourry's Sword of Light, it's likely that it takes place after the second season of the anime. However, in the prologue of the drama, Amelia states that it had been five years since they last met-problematic, since the anime seasons each occur within one year of the other. Premium also, of course, has its own manga adaptation...
 * Finally, there are cases of the dreaded Multiple Choice Past, especially in regards to Zelgadis. It's never mentioned in the anime, but in the novels it's stated that he was a criminal during his time with Rezo after he was initially turned into a chimera, and it gave him a bad reputation. Also, the applications of magic vary heavily to the point of convolution.
 * The various works of Leiji Matsumoto, which often share characters and have at tendency to re-tell stories from different points of view, could be the trope namer for this. Examples include:
 * Captain Harlock's ship, Arcadia, has two vastly different appearances throughout the shows in which it appears. Although this change was supposedly made due to a copyright conflict, no explanation is ever mentioned within the show. "Endless Odyssey" takes this to an extreme by showing one version in present times, and the other version in flashbacks.
 * Tochiro, the man who build the Arcadia, dies three different times in three different ways.
 * The film "My Youth in Arcadia explains how Harlock lost his eye and gives him a military career before he turned to piracy. However, some shows such as "Cosmo Warrior Zero" neglect to include his lost eye at all.
 * In "Space Pirate Captain Harlock" And "Endless Oddysey," Queen Emeraldas and Tochiro have a child named Mayu, who is never mentioned in any other series.
 * Some shows hint that Emeraldas and Maetal of Galaxy Express 999 may be sisters, even twins, despite the fact that in some of the shows the two are introduced for the first time.
 * Even more oddly, some speculation links Captain Harlock and Mamoru Kodai/Alex Wildstar as the same person. According to who you ask, they are either literally the same person, or Kodai pretended to be Harlock for his conveniences. Or something.
 * Similarly, most series have Torchiro and Harlock's friendship stretching back to their childhood, but "My Youth in Arcadia" shows them meeting for the first time while in the military.
 * Mimay has a radically different appearance from series to series: In most she has blue skin, blue hair, yellow eyes, and no mouth, but in a few instances, she is a rather normal-looking woman with blond hair and pale skin.
 * The series Captain Herlock: Endless Odyssey makes a valiant attempt to maintain continuity, and picks up with most of the main cast, including Harlock, Mimay, Kei, and most of the back-characters. Despite this, Tadashi Daiba's role manages to play out almost exactly as it did in previous series.
 * There is a glaring canonical gap of about 800 years between these overlapping stories. The character's apparent immortality is never mentioned.
 * It can be generally treated as a blend of a recycled cast of characters, implicit different continuities being treated as obviously different, and it can be a pretty good idea to consider nobody dead in any of the series if the body has not been incinerated.
 * For the most part, Digimon takes place in different continuities. However, there are still some pretty big snarls, mostly in the videogames. Digivolution lines get mixed and matched, changed, et cetera. Ryou Akiyama is somehow from Adventure, has encounters with the Digi-Destined, and gets sent to the Tamers universe by Milleniummon. None of this is addressed in either show, and for that matter, where is the other Ryou? Or his family? What happened to all of that data that Monodramon absorbed from Milleniummon? This thing was supposed to have surpassed the Sovereign. Speaking of, how many ultimate evil Digimon or ultimate godlike Digimon are there by now? So who's top dog? And how can there be a Black/Shadow Seraphimon if corrupting a Seraphimon causes a Daemon to be born? How did WarGreymon and MetalGarurumon DNA Digivolve if Gatomon still had her tail ring? Americanization also adds problems. Was Kokomon reborn? How did Diaboromon survive if the virus behind it was destroyed?
 * The WarGreymon and MetalGarurumon "DNA Digivolving" thing can be explain because in the original Japanese version they were merely fusing to become a more powerful Digimon of the same level. Where Jogress evolution (the evolving method of choice in season 2) was when two Digimon combined together to advance to the next level. The dub made a mistake in referring to WarGreymon and MetalGarurumon becoming Omnimon as digivolving.
 * This is part of an even bigger snarl that happens when you work the merchandise in, as some fans consider it canon and some don't. In the show proper, Ex Veemon and Stingmon become Paildramon for the first time (the process known to the US as DNA Digivolving) and a flashback to Omnimon is shown as The Smart Guy tells the newer characters that this has in fact happened before. However, the Japanese card game refers to the DNAs as "jogress" (join and progress) and Omnimon as "fusion" when giving the requirements for bringing Omnimon or Paildramon (and the like) into play. Really, it's as simple as "sometimes two Digimon turn into one badder 'mon. In Japan there's this card game with two names for this. They either do or don't mean the same thing."
 * Then some V-pets do say Omnimon is at a higher level. The easiest thing to say is that Digimon can keep getting stronger after Ultimate/Mega and just ignore whatever the level is called at that point.
 * This is only a problem, if at all, in the Adventure continuity. In the broader Digimon canon as a whole, it is accepted that a) Omegamon is the product of a Jogress evolution/DNA Digivolution, b) "fusion" is just another term for "jogress" and the English version's uniting the two under the same term is a rare case of it simplifying things, c) Ultimate/Mega level Digimon can evolve to other Ultimate/Mega Digimon, whether it's through Jogress evolution or otherwise, and d) Holy Rings like Tailmon's tail ring have absolutely no relevance to the process of Jogress evolution whatsoever and that point in Adventure 02 was the writers not listening. Indeed, Omegamon himself is the subject of such an evolution from one Ultimate to another in the Digimon Mini virtual pet line, evolving from WarGreymon alone. Also, pretty much every Mode Change ever is an example of this, being little more than evolving to another Ultimate that happens to be a variation on the prior form.
 * At first, we're told in supplementary materials that only "Dramon" are true dragons, so Greymon doesn't count. Then we meet ancestor of all dragons, Dracomon, leader of all dragons, Examon and Azulongmon, strongest of the four great dragons.
 * Dracomon, as the ancestor, is the one who set the archetype, so it could be argued that in-universe the "dra" part of the name actually comes from "Dracomon" and refers to him - all Dramon bear his name, data and attributes, not the other way around, and that's what makes them Dramon. Meanwhile, Examon is Dracomon's highest evolved form; at any rate, it is officially classed as a Holy Knight Digimon. That said, it's never been established that only Dramon are true dragons - there have been plenty of non-Dramon dragons, including ones as old as Veemon's family, as new as Shoutmon, and as-meant-to-be-a-dragon-as-possible as Majiramon the dragon Deva. Hell, a very sizable chunk of the Dragon's Roar family are not Dramon. Also, Qinglongmon has his own group/theme-naming to which to adhere. On the opposite end of the debacle, there's Birdramon and Ebidramon, who, save for the names (at least one of which predates the whole "Dramon" concept) have never been indicated to be any sort of dragon at all...
 * Actually, Ebidramon is related to Dramon digimon in a way. He's a subspecies of the Seadramon family, and at an early point in the series served as the Perfect level for the family before the Ultimate level was introduced by the Pendulum V-Pet series. That same V-Pet Series also moved Ebidramon and several other digimon up and down the evolution levels, creating even more snarl.
 * Shadow Seraphimon wasn't a corrupted Seraphimon, Mercurymon just absorbed his data, the name is really misleading. Not only that, but he (Seraphimon) gave the digidestined fighting Mercurymon a much needed powerup...granted he had been reincarnated and was still an egg.
 * A "dark Seraphimon" that is a virus version of Seraphimon does exist, BlackSeraphimon. The difference here is somewhat distinct: there is a difference between a "fallen Seraphimon" and a "Seraphimon that happens to be a virus-attribute variant". Not all virus-attribute Digimon are evil (see: Guilmon and Wormmon)
 * However, as you can see, a lot of this comes from Fan Wank regarding merchandise. It is not always possible to fit everything you see on a trading card or virtual pet into the show, but the show does not contradict itself on many things... however, Ryo has it as bad as any comic book character. The Ryo-related aspects of Digimon Adventure 02 that seem random and nonsensical are explained in the games... but once you take them into account, some of the events of Digimon Tamers are thrown off.
 * Magical Girl Lyrical Nanoha is starting to run into this with two series of manga, Mahou Shoujo Lyrical Nanoha ViVid and Mahou Senki Lyrical Nanoha Force, running at the same time. They mostly manage to stay separate, but occasionally they contradict one another.
 * Tengen Toppa Gurren Lagann started off with a prologue involving Simon/Kamina/Caption Garlocks (fans argue this fact constantly) waging war against "All the lights in the sky." This is similar to battles late in the series, but never really fits any of them. The producers admitted that this was a fluke on their part, that it was meant to be Shout-Out to Arcadia, and that they never got around to building up to that scene in the main series. This had led fans to suggest that this scene is an alternate universe, a fantasy of Boota, an alternate timeline in which Kamina leads Dai-Gurren into space/Simon is sent back in time to battle the Anti-Spirals as well as become Kamina's father.
 * The Kinnikuman manga has a rather bad example: when Geronimo attacks Akuma Shogun, we see a group of choujin watching Geronimo's beat-down, with Geronimo being in the group. In other words, Geronimo's watching himself get beaten.

Comic Books

 * Post-Crisis, Hawkman is the poster child for this trope. Originally, the Hawkworld mini-series was supposed to retell the origins of the Silver Age Hawkman, but after it became a success, DC commissioned a Hawkworld regular series, taking place where the mini-series left off, resulting in a total reboot of Hawkman's continuity (a la the post-Crisis reboot of Wonder Woman), despite the fact that the Silver Age Hawkman was already established in post-Crisis continuity, and prior to the relaunch, briefly joined the Justice League International. This was followed up with several attempts at fixes, each of which simply made the problem worse. Hawkman's continuity was described, according to DC editor Mike Carlin, as "radioactive". In the wake of Zero Hour, the various incarnations collapsed into the "Hawkgod", who was essentially an Anthropomorphic Personification of the Hawk-Continuity Snarl. After this, DC editorial declared the character off-limits to the writers from 1996-2001.
 * The cover to Hawkman (Vol. 3) #27, published in December 1995, shown above, pretty much describes Hawkman's continuity at the time.
 * While all of this Continuity Snarl was happening, Hawkman and Hawkgirl's son appeared as a minor character in Neil Gaiman's The Sandman, eventually resulting in their grandson Daniel Hall succeeding Morpheus as the anthropomorphic representation of dreams.
 * Carter Hall, the Golden Age Hawkman, was eventually pulled out of the snarl in the pages of JSA. The Silver Age version is still in limbo. Carter had a few of the Silver Age concepts (most notably a connection to Thanagar) attached to him during the process. He also includes a simplification of one aspect of the Hawkgod; the Hawkgod's previous avatars included several of DC's historical characters with vague connections to hawks, and these have been retconned into Carter's former incarnations.
 * And now Jim Starlin, for reasons known only to himself, has written a Hawkman special in which a godlike-being points out to Hall that his Egyptian origin doesn't make sense, and insists on calling him by the Silver Age version's name. Just when you thought it was safe to go back in The DCU...
 * They did one where they merged the "Thanagarian Police officer" Hawkman with the "Egyptian Warrior re-incarnated over time" Hawkman into one being. It seemed to work, for a time. The DCAU went with two Hawkmen, but subverted them in . It actually ended up making a lot more sense.
 * An admirable, if a bit simplified, attempt to explain Hawkman's continuity exists here.
 * The whole deal with the X-Men comics. A lot of it is the Kudzu Plot started with Claremont, but a lot of it comes from the loads of Ret Cons and counter Ret Cons recently.
 * One example is Jean. Until the late 1990s, it was (relatively) simple. Jean was Jean. Phoenix was (retconned into) a cosmic entity that took her identity, and Madelyne Pryor was her clone. Then those Running the Asylum couldn't get that straight, and turned it into this. The Summers' Tangled Family Tree got worse and worse from the 1990s onward.
 * During Grant Morrison's run on the book, the X-Men travelled to China where a mutant named Xorn was held prisoner, released Xorn, and took him in as member of the team. Xorn turned out to be Magneto in disguise. The degree to which this made sense is debatable (since when does Magneto speak perfect Chinese? Why didn't Wolverine smell him?) but it was at least easy to follow so far. But then Magneto started doing drugs and herding people into ovens, and when Morrison left the book, the remaining X-Book writers couldn't retcon him as an impostor fast enough. So it was someone pretending to be Magneto pretending to be Xorn. Then it turned out there was another Xorn, who was the brother of ... the fake Xorn ... or something. There's a reason they don't mention Xorn much these days.
 * Stand forward, the Legion of Super-Heroes. The Websnark rant linked above goes into detail, but it's worth noting that there have been at least three separate reboots of the series, that there have also been a number of smaller Cosmic Retcons that involved things like long-standing characters being retroactively replaced with entirely different people, and that DC Comics at one point featured two vastly different versions of the group. Legion of Three Worlds teamed up all three versions, put the later two on a bus, and ignored the five year gap version, leaving only one Legion, the first one, removing some problems but leaving Gates, Bart Allen and XS.  Then the New 52 came along.  The Legion limped along with relatively few continuity changes, something shared by only Batman and Green Lantern and was finally cancelled, revealing that it took place on a world similar but not identical to Earth 2.
 * The Wonder Woman mythos has gotten increasingly confused due to Time Travel and Cosmic Retcons, but poor Donna Troy is a particularly notorious example. She was created due to a continuity error—the writer didn't realize that "Wonder Girl" was just Wonder Woman as a teenager and crossed her over with herself—and has since been the subject of at least five stories attempting to establish just what her ever-more-complicated origin is. The fact that, following the Crisis, Wonder Woman was retroactively declared not to have been active in the early years of current continuity, while Donna was still supposed to have been a Teen Titan alongside the original Aqualad, Speedy, Robin and Kid Flash certainly didn't help.
 * John Byrne introduced a fix, having WW's mother Time Travel back to the forties and become the "first" Wonder Woman, which helped... but he also introduced the "Dark Angel" concept, which retconned Donna as a sort of cosmic Chew Toy repeatedly reincarnated into horrible fates, and sent her straight into Continuity Limbo for a few years. This all has earned Donna the nickname "Identity Crisis Lass" in some circles. Also "The continuity error who walks like a woman!" It was finally declared in 52 that Donna Troy was a symptom of the chaos caused by having multiple realities interacting with each other.
 * Post-Crisis Power Girl went through sooo much of this - she's a Kryptonian, she's an Atlantean - she's a weird metahuman - nobody knows. Finally, it was declared that she was a survivor of the pre-Crisis multiverse and her Continuity Snarl was the universe trying to "fit her in" and failing. Now she is considered to be the Supergirl analog of the original (pre-Crisis) Earth-Two.
 * Yes, this means now there's a second Power Girl in current continuity Earth-Two. Writers just don't know what wasp nests to leave alone.
 * Supergirl's continuity is pretty tricky, too. There have been at least half a dozen different characters to use the name. Oh, and some of those might be the same people, and some of them, even post-Crisis, might never have existed.
 * Is Marvel Comics' Superman equivalent The Sentry a Silver Age hero who erased all knowledge of his existence so an evil being called The Void would not exist? Or is he a superhuman with mental problems who read a comic book and adopted the identity? Or is he the results of Super Serum experiments with The Void being actually a part of his fragmented mind? Who knows?
 * It's quite possible even he doesn't know.
 * Drug addict who accidentally drank God to get high. Basically.
 * One word: Superboy. John Byrne's reboot of Superman caused all kinds of problems since, for one, his Superman was never Superboy. No Superboy to hang out in the 30th Century with the Legion of Super Heroes. Then you have all of the splintering of Superboy - clone, Superboy Prime, Pocket Universe Superboy... make it stop!
 * While not as extreme as some of the examples here, Green Arrow has had numerous minor, but confusing, problems since Oliver Queen came back from the dead.
 * The problems began when novelist Brad Meltzer wrote a Green Arrow story called The Archer's Quest centering upon Oliver Queen going on a road trip with former sidekick Roy Harper to retrieve items that could be used to discover his secret identity. The problem with that is that Oliver Queen hadn't had a secret identity in years! In fact, in the Quiver storyline written by Kevin Smith (which came out less than a year before Meltzer's story) the main piece of evidence Batman used to convince a resurrected and amnesiac Oliver Queen that he HAD been dead was newspaper articles which used his real name while discussing his death.
 * Another problem was the revelation that the whole Archer's Quest was a ruse and that Ollie had really been trying to recover a photograph which proved that he had been present on the day his illegitimate son Connor Hawke was born and that Ollie, ipso facto, was a dead beat dad. The problem is that this scenario is completely implausible given the circumstances under which Ollie originally found out that Connor (who he had been traveling with for a while before his death) was his son - he had been told by the truth by his best buddy Hal Jordan, who was (at the time) nigh-omnipotent with the power of all The Guardians Of The Univers Minus One. For Meltzer's scenario to make sense, we have to believe that Hal Jordan is capable of being able to see the DNA of a person by looking at them but is unable to tell when his best friend is lying about having no idea he had an illegitimate son.
 * It Got Worse several years down the line when Judd Winick Jossed a fan theory that sprang up to explain away the discrepancy. The idea was that Ollie knew about Connor and tried to do the honorable thing by proposing to Connor's mother but that she had (having always been portrayed as an independent, free-spirited hippie) rejected him because she didn't want to marry only because he felt guilty/didn't want to get tied down. Instead, Winick wrote a flashback scene where Connor's mom approached Ollie and was sarcastically wished good luck in trying to prove the baby was his in court. This scene apparently took place BEFORE the shipwrecking incident which inspired Ollie to become Green Arrow, as he tracks her down once he gets back to civilization and is there to have his photo taken with Connor before he has a fight with Sandra and walks out of her life again.
 * What makes this truly awful is this scene was meant to bookend the excellent Green Arrow: Year One mini-series by Andy Diggle. Suffice it to say that Green Arrow fans who have read that book find it hard to believe that the man Oliver is at the end of the story would ever abandon a child in need, much less his own son.
 * The flashback also changes Sandra Hawke, who had always been portrayed as a half-African/half-Korean woman who favored her Korean mother into a pouty-lipped African woman with dreadlocks.
 * Speaking of romantic problems, Judd Winick did a major disservice to the character when he decided to join Green Arrow and long-time girlfriend Black Canary together again off-camera, only to break them up. He did this by having Green Arrow suddenly decide to have a one-night-stand with the niece of a friend, despite the fact that Ollie was ready to propose to Black Canary not a few months earlier in the final chapter of The Archer's Quest by Brad Meltzer! Indeed, the dialogue in the scene where Ollie nearly proposes suggested that he and Dinah had gone out a few times since his resurrection but that she wasn't ready to date exclusively, let alone get married.
 * Judd Winick also caused problems with his Heading Into The Light storyline, which was meant to be a lead-in to Infinite Crisis. In the end, here were so many issues with the storyline that DC Comics had to retroactively declare that Heading Into The Light took place AFTER Infinite Crisis, even though the story ends with a wounded Oliver Queen having visions of himself in other realities.
 * Some problems also sprang up over the issue in which Doctor Light drained Kimiyo Hoshi of her powers. She appeared in Infinite Crisis and Birds of Prey with her powers intact, while other stories ran with the premise of having her powerless. This was eventually handwaved in an issue of JusticeLeague, which had Kimiyo mention that while she still retained her abilities, they were now malfunctioning and only worked on certain random occasions.
 * Ultimate Marvel has had a few problems with this where its version of Iron Man is concerned. The Ultimate Iron Man miniseries by Orson Scott Card, while good on its own, is difficult to fit into continuity with the Ultimates series. Another origin story featured in an issue of Ultimate Marvel Team-Up created further problems. Although Brian Michael Bendis, who wrote the latter story, has suggested that some of Ultimate Team-Up is dubiously canon, it remains to be seen how or if the former will be reconciled.
 * The Ultimate Iron Man miniseries has recently been retconned to be a movie about Tony Stark's life that ignores the truth in favour of bizarre sci-fi.
 * Ultimate Fantastic Four is the source of a few issues as well. In Ultimate Spider-Man and The Ultimates the Fantastic Four are referenced and Reed Richards is a notable enough scientist to have a building at ESU named after him, but very early on in Ultimate Fantastic Four, before the team comes together, there are references to The Ultimates.
 * This one happens because of a change in plans. Originally, the Fantastic Four we were seeing in Ultimate Spider-Man and the such were going to be adults, while Ultimate Fantastic Four would take place a decade or so in the rest of the line's past, establishing the FF as the first super heroes and cornerstones of heroic society in the Ultimate U. The plan got muddled and changed, but it's very apparent when Sue Storm, 16-ish in UFF, shows up during Ultimate Spider-Man's "Clone Saga" and is clearly in her late 20s/early 30s.
 * The Crossing, a Crisis Crossover featuring The Avengers, is such a snarl that even Linkara refuses to review it, partly because it's nearly impossible to tell when it begins or ends. Basically, Iron Man turns evil and helps Kang try to take over the world, but who is on who's side changes from issue to issue. Eventually, Kurt Busiek rendered the whole thing moot in Avengers Forever by stating that the entire thing was Immortus trolling the superhero community so that they'd leave other planets alone, and that almost everyone involved was a Space Phantom. After the Heroes Reborn/Heroes Return debacle, the Crossing was pretty much never brought up again.
 * Busiek also used Avengers Forever to untangle the very snarled continuity of The Vision. For decades, the Vision's origin story had him being created from the remains of the original Human Torch. But after the writers of West Coast Avengers decided to re-introduce the Torch to modern continuity in the late 80s, the Vision's origin was retconned, invalidating alot of stories and raising alot of questions about where the Vision did come from. Enter Busiek, who explained everything by having Immortus use a time-altering MacGuffin to change history, so that two contradictory events; the Torch being rebuilt and the Torch not being rebuilt, both happened at the same time. Neat, huh?
 * The Uncle Scrooge comics briefly endured this after Boom Studios acquired the license. The first eight issues under this publisher seemed to follow the comics' standard continuity—and then the next eight tried to tie the series into the DuckTales (1987) TV show, which was only a loose adaptation with noticeable differences (in the comics, there was never a Launchpad, Donald didn't join the navy and Glomgold was an Afrikaner). As of issue #400, the comics seem to have returned to their original continuity, and a completely separate DuckTales (1987) title has since been released. So naturally this new series would feature a brief appearance by John Rockerduck, a Scrooge antagonist from the comics who never appeared in DuckTales (1987)!
 * The symbiotes from Spider-Man. First, the Venom suit was just an alien costume. Then it was retconned into being alive. Then, when the writers wanted to turn it into a villain, it was retconned that the suit made Spider-Man go insane and he had to get rid of it (originally, he was trying to destroy just because it was attatching itself to him, which is a bit harsh for a guy like Spidey). It was later shown the the suits fed off strong hosts as a sort of Social Darwinist. Then it was revealed to feed off negative emotions such as hate and anger. Then they were shown to live in the Negative Zone... no wait, there was a separate planet of them. Oh, and Toxin proved that not all of them are born evil after all. Oh, and Carnage has had about three symbiotes get destroyed but no one ever remembers those stories.
 * As the Batman franchise was one of the few properties not completely rebooted during DC's New 52 initiative, numerous continuity problems have arisen over the bits of Bat-history that were altered. A particular source of contention is how Cassandra Cain and Stephanie Brown could fit into the new, condensed five year timeline given some of the statements made in the new Batgirl title. Though it has been confirmed that Cain will appear in Batman Inc. at some point, how her history could be reconciled has not yet been mentioned.

Fan Works

 * Averted (so far as of July 2020) with The Teraverse (and its super-series A Brane of Extraordinary Women). Despite having a dozen or more writers continually adding in new sources and elements to this Mega Crossover, there is sufficient coordination to maintain a consistent history, sometimes down to the day, and implement changes and expansions across multiple story lines.

Film

 * In the process of creating prequels for the X-Men film series, different creative teams have introduced a number of discrepancies in the franchise - in fact, the only reason they're meant to be in the same continuity is the presence of Wolverine in all five films and the character of William Stryker. Almost all of the films have continuity snarls with other installments:
 * Emma Frost is introduced as a woman in her late 20's/early 30's in First Class (which takes place in 1962), but is seen as a teenager in Origins (which chronologically happens 17 years later, during the Three Mile Island incident in 1979).
 * This isn't the only problem with ages; Cyclops is portrayed as a teenager in 1979 during Wolverine, but is portrayed as a man in his mid to late twenties in the original X-Men trilogy, which takes place 20 or so years later. James Marsden was 27 when he portrayed Cyclops in the original X-Men, about ten years too young.
 * The process by which Wolverine received his adamantium claws changes from film to film. In X1, dialogue and x-rays show that he had mechanical pistons and claws grafted into his arms. X 2 X Men United hints that the adamantium was injected and shaped by doctors, and (in a flashback) Logan is seen fighting off several doctors who've been working on him before escaping the Alkali Lake facility covered in blood. In Origins, the adamantium bonding process is hands-free, no doctors ever work on Logan, and the adamantium is grafted to his bone claws, something he wasn't mentioned as having in the following films.
 * Charles is paralyzed in First Class, but is seen as an older man walking around (with Magneto, no less) when they visit the young Jean Grey in The Last Stand and when he appears in Origins. Hank McCoy becomes Beast in First Class, but is shown on a television screen (in human form) in X2. Cerebro was built by the CIA in First Class, but was apparently built by Xavier and Magneto in X1. The discovery of the mutant gene is new (and eventually leads to America and Russia uniting to kill mutants) in 1962 in First Class, but Congress is surprised and shocked by the existence of mutants in the "present day" of X1, which happens 40 years later.
 * Also in Wolverine, Sabertooth never had his memory erased and should know his own brother. In X1, which was released first, it seems that Sabertooth does not know Logan, looks completely different, and is near-mute.
 * In First Class, it is established that Mystique and Prof. X grew up together. Seems odd that she would be so casual about attempting to kill him in X1 and at no point did Charles express any real knowledge of her outside of being Mangeto's lackey.
 * In X1, it is implied that Magneto built his own telepathy-blocking helmet and it was a new addition since Prof. X was surprised he had one. In First Class, it was built by Sebastian Shaw and Prof. X had full knowledge of it.
 * Matthew Vaughn, director of First Class, has stated he tried to fit with only the trilogy instead of Wolverine. Too bad Fox and the makers of said movie's Blu-Ray didn't listen, and the Cerebro bonus feature profiling most mutants try to put all 5 films in the same timeline... (as mentioned above, Emma Frost is the most senseless)
 * He also failed to make Havoc and Beast fit into the continuity of the original trilogy. Havoc is Cyclops' younger brother in the comic continuity; Havoc is a teenager in 1962, making him at least 16 years older than Cyclops. Beast also has this issue, as in order to make the ages work, he would have had to be 60 or so years old during the events of X-Men 3 (Kelsey Grammer was 51 during filming).
 * The Star Wars saga caused several snarls, with some caused due to conflicting Expanded Universe material, and some due to the series' jump from the original trilogy to the prequels:
 * Obi-Wan has several statements in the OT that turn out to be Half Truth at best (which does fit in with his character; he is one of the most prominent examples of Half Truth). He claimed he didn't own a droid in A New Hope, but did during the prequels. He apparently didn't know that Leia was Luke's sister at first, despite being present when they were both born and named. He never specifically stated that Yoda was his mentor, but it was certainly the implication in The Empire Strikes Back (before it's revealed that it was Qui-Gon Jinn, then subsequently patched up by showing Yoda trained young Jedi before they grow up and get another mentor). Obi-Wan also mentions that he was as reckless as Luke when he was his age (but not according to the prequels, which show him following the rules more rigidly than anyone else).
 * Leia claimed to have remembered her mother in Return of the Jedi, but Luke was born first, then Leia and Padme died in childbirth in Revenge of the Sith.
 * In The Empire Strikes Back, Darth Vader does not seem to recognize C-3PO, despite creating him in The Phantom Menace. The Expanded Universe attempted to rectify this in a (non-canon) story called "Thank The Maker", where Vader reminisces about his mother and 3PO when he's at Cloud City.
 * 3PO droids are common throughout the galaxy. The fact that C-3PO was built by a child out of the junked remains of several different 3PO variants instead of assembled in the Cybot Galactica factory didn't result in any visual difference. The color of their outer plating aside, all 3POs look the same. Since there are millions (if not billions) of them in circulation, it's no surprise that Vader wouldn't necessarily recognize the specific one he built in his youth.
 * Chewbacca apparently has no respect for Jedi in A New Hope, despite fighting the Clone Wars alongside Yoda on his home planet in Revenge of the Sith.
 * Chewie, unlike Han, is never seen to scoff at Obi-Wan's Jedi teachings, and since he doesn't actually speak in any way the audience can comprehend, we really have no indication what he thinks about Jedi.
 * Revenge of the Sith reveals that it took roughly 20 years to build the Death Star (from the time Luke and Leia are born, a rough frame of the structure is being built) without anyone realizing it. In Return of the Jedi, the Death Star II only takes 3–4 years to be fully functional and mostly-built. The apty-named novel "Death Star" tries to address this, going over numerous problems that came up over the course of its construction (including at least one instance of the superlaser having to be stripped out and redesigned). Death Star II, deaspite being a ludicrous 20 times larger than Death Star I, could be built much more quickly because by that point the Empire actually knew how to build a Death Star.
 * In A New Hope, the Jedi had been gone for so long that some people (like Han Solo) no longer believe in the Force. When Obi-Wan whipped out a lightsaber, it was very shocking to the patrons in Mos Eisley. The Prequel Trilogy (ostensibly set twenty years before) has scores of Jedi walking around on several planets as a normal part of everyday political negotiations, with people not even batting an eye when witnessing Force powers or lightsabers.
 * Obi-Wan and Yoda supposedly left Luke on Tatooine with the purpose of training him later. When that day came, Yoda acted surprised and even argued with Obi-Wan as to whether or not Luke should be trained. This could, however, be interpreted as Yoda just being unsure whether Luke is worthy of Jedi training, with the justifiable fear that he might end up like his father.
 * Within the original trilogy, Luke and Leia are set up as possible love interests (to the point that a deleted scene shows them about to kiss), only to be revealed as siblings later on.
 * Obi-Wan's explanation of Darth Vader's turn seems awkward when it is later revealed that Vader was Luke's father.
 * Obi-Wan, and Anakin after he removes the Vader mask in ROTJ, are played by actors in their 60s and 70s, respectively, suggesting they would have been in their 40s and 50s when Luke and Leia were born. Instead, they were shown to be in their 20s and late 30s.
 * Canonically, Obi-Wan died at 57 (only 5 years younger than Alec Guinness during filming). Anakin, on the other hand, was 46 (26 years below Sebastian Shaw!).
 * The Expanded Universe had, prior to the prequel trilogy, assumed that Obi-Wan had met and trained an adult Anakin, as nothing in the original trilogy even hinted at Jedi being brought in for training as young children. Thus, the EU soruces listed him as being only 5 years younger than Obi-Wan.
 * Highlander is one of the kings of this trope. Each of the original films screwed up the continuity more and more, and then the series was added in and then there are things like Search For Vengeance, and the Animated Series. This is another universe that will give you a headache if you try to figure it out.
 * Minor by comparison to most of the other examples, but Tim Burton's Batman featured a black Harvey Dent, whereas when he was used as a character in the Joel Schumacher-directed sequels, he was depicted as white. Or at least, half of him is white.

Literature

 * Because he was constantly revising his unpublished works, JRR Tolkien managed to create a Continuity Snarl all by himself (which is probably why they were unpublished). His son Christopher edited many of them together into The Silmarillion, trying his best to come up with a version that didn't contradict itself.
 * The Land of Oz suffered from continuity problems from L. Frank Baum's hands. This included whether they used money; whether they could die; and where Ozma came from.
 * He managed to get a Continuity Snarl with two books. In the first book, the Scarecrow is Offered the Crown of the Emerald City; Glinda has the flying monkeys carry him back there so he can claim it. In the second book, when the Scarecrow goes back to Glinda for help regaining his crown, she tells him that he's not entitled to it, it's Ozma's.
 * H.P. Lovecraft's Cthulhu mythos. Lovecraft himself was not always very consistent with various details between his stories, and several of the other authors who continued his work had various contradicting views of the mythos, leading to much confusion for anybody trying to fit all the stories into a single continuity.
 * Part of the reason behind that is that, at the time, Lovecraft had a very "pulp fiction" attitude towards his stories - not only did he have very little intent to create a cohesive continuity framework into which all of his stories could be inserted, but he tended to see each story as somewhat self-sufficient and exclusive. Mentioning the same occult book in multiple stories or inserting a reference to a character from another story was more a method to create the feeling of artificial depth to the story at hand rather than trying to imply they all took place in a consistent universe. Lovecraft never really bothered to maintain continuity in his OWN stories, let alone all the stories written by his friends and associates that used shared references.
 * Furthermore, Lovecraft aimed to create the feel of ancient myths by adding in deliberate inconsistencies, depending on what source the characters of a particular story gain their information. There's at least three different species as candidates for the title of the Great Old Ones, for example, as well as the more famous interpretation which Derleth embraced that the name refers to unique creatures of immense power.


 * The Star Wars Expanded Universe is so large almost no fans have read even most of it. The lack of clarity on what is and isn't canon doesn't help either.
 * Discworld suffers somewhat from this, but it is explained in-universe as the results of Time shattering and having to be stitched back together by the History Monks.  Twice. They only get away with it because of the extraordinary power of the human mind to deceive itself.
 * In his later years, Kir Bulychyov admitted that he never reread any books in his Adventures of Alyssa cycle, which would explain the many, many continuity problems that emerged over time. Krys, a recurring villain, had about three different (contradictory) origins and six different explanations of how his powers worked, his companion, Vesel'chak U, gained and lost powers, the chronology has been anything but consistent and don't even get started on when half of the novels were supposed to take place relative to each other. The fact that Kir Bulychyov died a few years ago doesn't help at all.
 * Chris Roberson aims for this by intention—as a kid, he loved reading comic books and seeing all the ways they interconnected. Pretty much everything he writes that isn't a tie-in to Warhammer 40,000 is in a single setting, but he explicitly uses the "many worlds" model of quantum mechanics, and slight deviations lead to massive differences over a relatively short period of time. Attempting to fit his works into a single continuity would be arguably meaningless, and it's uncertain whether even he knows what he's doing half the time.
 * An entire cottage industry has sprung up around trying to wrestle the Sherlock Holmes stories into continuity — not only with each other, but with actual history.
 * They call themselves the Baker Street Irregulars after the street urchins Holmes often calls upon for help. Basically, their version of Trekkies.
 * The Sonic the Hedgehog mini-novels made by Michael Teitelbaum and Ron Zalme; the novels clearly take place in the SatAM universe, yet the Robotnik used in it is the one from Adventures of Sonic the Hedgehog. How that fits into continuity is anyone's guess.
 * About halfway through the first Bionicle book, Tale of the Toa, the writer starts mentioning the tools of the Toa Nuva, and how the Toa use them. Yet they only turn into Toa Nuva at the end of the second novel. The confusion came about because the author, who wasn't well versed in the story and its characters to begin with, had to churn out the books real fast, all in 2003, which meant that besides that year's story, those of '01 and '02 also had to be written down. She thus accidentally mixed up the original Toa and their tools from the first year with their advanced Nuva forms from the second.
 * A lot of scenes also differ in their presentation from the source material, like how the Toa received their Golden Masks, and the entire final battle with the Manas and Makuta, the latter of which didn't even occur in the book, despite being the Grand Finale of that year. Tons of scenes are written in a way that makes the book unwarrantable for a Compressed Adaptation title (as in, the left-out events simply cannot be spliced in between the chapters). These could be forgiven, were the book meant to be a simple adaptation, or a "new take" on the story, but it was supposedly intended to be part of the official timeline.
 * In The Book Of Night With Moon Tom and Carl are stated as Advisories, which would put it before the second book in the other series. Then Nita shows up... and says that Dairine has passed Ordeal, which is the plot of the third book!

Live-Action TV

 * Countless Doctor Who fans learnt to shudder when the topic of what exact decade(s) the UNIT stories were set in is raised, before the new series demonstrated how much worse it could get. Precisely when the UNIT stories were set may be unclear, but at least we know which order they took place in. With the new series and Spin-Offs, we don't even know that. There are sound arguments that Revenge of the Slitheen happened after "Smith and Jones", and equally sound arguments it happened first.
 * The Eighth Doctor's continuity doesn't even try to make sense simultaneously. The only definitively canon story is the telemovie, for the novels, audios and comics made it clear early on that they're not concerned with outright contradicting each other for the sake of telling their own stories.
 * There's the Cybersnarl created by the incompetent attempts to tie "Attack of the Cybermen" in with "The Tenth Planet", "The Tomb of the Cybermen" and "The Invasion".
 * These are by no means the only fraught areas of Doctor Who continuity. In what order did the original series' Dalek stories happen? (In particular, when does The Daleks take place and why are the Daleks in that story so different from all others seen later?) How many Doctors have there been (watch The Brain of Morbius, although the novelisation clears it up a bit)? What was Atlantis like, and how did it sink? And how many times did it sink (And yes, this question is more complicated than it first appears)? How do Time Lord family relationships - in particular, the Doctor's - work? What are the Laws of Time and for that matter, are they laws in the scientific or legal sense? And most of that list arises just from the TV series.
 * It's probable that everything is canon, but with all the time travel that goes on, the Doctor's past adventures and even massive things like the fabric of Time Lord society get changed by all of this all the time. The problem is then understanding what's canon right NOW.
 * And now that
 * The Time War that occured sometime between the Eighth and Ninth incarnations is sometimes used by the writers to explain continuity errors.
 * Another possible theory which is occasionall kicked around in the fandom is that since we know, due to classic-era episodes like Inferno plus the events in various new-era Series 2 episodes, that the TARDIS can slip "sideways in time" into alternate-history universes, it's entirely possible that the TARDIS has been doing so all along without the Doctor realizing it.
 * In the immortal words of a leading who-fan: "Continuity? What continuity?"
 * As mentioned above, Star Trek also suffers from this, despite efforts from the writers to avoid this.
 * A particularly embarrassing debate is the question of why Klingons look completely different in the original series to the rest. It was Lampshaded in one Deep Space Nine episode, but deliberately wasn't explained (the Deep Space Nine writers stated they realised any explanation, especially a virus-based one (which they had considered but abandoned) would be underwhelming, forced and ridiculous so decided to acknowledge it in a humorous way but not insult the fanbase with a horrible technobabble solution). Enterprise decided to create an explanation regardless. Apparently, reconstructive surgery in the Enterprise episode suggests that individual gene therapy became possible between TOS and Deep Space Nine, thus explaining Kang, Kor, and Koloth's sudden appearances of ridges in the latter. And yes, the whole story is every bit as trite as the DS9 writers had feared.
 * The change in their MO from "The Russians IN SPACE! " to Proud Warrior Race Guys is hinted at in one recently-affected Klingon mentioning having felt fear for the first time since childhood. Apparently they got more underhanded because their personalities were also altered to be more human.
 * In the prequel comic to Star Trek (2009), Star Trek: Countdown, it's stated that Nero's crew ritualistically disfigured themselves as a demonstration of mourning for their lost homeworld. You can see in the very first scene with Nero that he has both pointed ears intact, while later in the movie one ear has had the point cut off. The same scene also has much more prominent brow ridges on Nero's face than later in the movie, so it's likely that distorting their ridges was another part of the mourning, along with the tattoos.
 * Furthermore, the tattoos sported by Nero's crew are given an explanation: Romulan tradition states that when a family member passes away, they apply dyes to their skins, and mourn. When the patterns fade, they move on with their lives. Nero's crew tattooed the symbols onto their bodies, so that they would never move on from the loss of Romulus.
 * And then there's the Eugenics Wars. In the 1967 episode "Space Seed", it's established that the Earth was devastated in the 1990s by an epic war fought against genetically-engineered supermen. Trouble is, Star Trek was still going strong by the time the actual '90s rolled around. And some episodes made in that time and afterwards seem to suggest that the '90s happened like they did in Real Life. But the Eugenics Wars are still Canon and an important part of Star Trek's Backstory as it's the origin of Khan. This has never really been officially resolved, although author Greg Cox wrote a series of Star Trek novels covering the Eugenics Wars, depicting them as happening in secret and trying to match it all up with real history.
 * Vulcan telepathy is treated differently by Star Trek: Enterprise compared to the other series. Despite other series having established it was a common accepted part of Vulcan society for thousands of years (TNG's "Gambit" establishes it's been part of Vulcan society for well over 2,000 years), in "Enterprise" it's considered much rarer, much more stigmatised, to the point where the mind-meld is commonly believed to be only possible by a very few. This contrasts to other series' having Vulcans being very aware of their own wide-spread telepathic history to the point where they knew it was being used in psionic battles before Surak's reformations and pieces of psionic resonators were established museum items.
 * The Big Bang Theory: In the season 1 episode "The Hamburger Prostulate" mentions that Sheldon is allergic to cats, but later episodes mention that he had a cat when he was a kid. "The Plimpton Stimulation" even states that getting a pet was against the "Roommate Agreement" unless it was necessary, like a Seeing Eye Dog.
 * Possibly lampshaded in "The Zazzy Substitution" (Season 4, Ep 3) where Sheldon reacts to his breakup with Amy by getting a cat ... then several more. 25 in all.
 * Though people can develop (and lose) allergies as they get older, or pass through different developmentalstages, so it is possible that Sheldon had a temporary cat allergy.
 * Don't try and figure out M*A*S*H's timeline. Many have tried and it just gave them a headache:
 * To get into the show's worst offenses, when Colonel Potter takes over the camp, it's explicitly stated to be September 19, 1952, but a later episode opened on New Year's Eve, 1950 with Potter and Winchester there. And The Korean War started in late June 1950, so apparently the show's first five seasons with Colonel Blake and Frank took place over the course of barely more than five months. And early episodes with Blake and Frank tended to give the year as 1951 or 1952. And the September 19, 1952 date doesn't work very well even on its own since it requires that eight seasons take place over the course of ten months.
 * Not only that, but they had a Christmas episode in each of the seasons and a few episodes that would take up several months to a whole year.
 * One episode starts with the new year and ends with the next year.
 * In a Season 3 episode, Hawkeye talks about the death of Doctor Charles Drew and says it was "last April." Drew died in April 1950. That would put this episode some time in 1951.
 * A few episodes later in Season 3, Hawkeye says he's been in Korea for two years. If he got there when the war broke out in June 1950, which doesn't seem likely since he was drafted, that would make it some time in 1952 at the earliest.
 * In The Suite Life of Zack and Cody, Maddie asks London's help to pass gym when she realizes that, despite her pampered lifestyle, the rich girl is in great shape. In the sequel show, Suite Life On Deck, London suddenly needs Zack's help to pass gym.
 * iCarly, Zoey101 and Victorious share a universe. Drake and Josh is a piece of Recursive Canon in that universe, and has Drake Bell the actor (not Drake Parker the character), show up in Zoey 101. Then in iStart A Fan War, an episode of iCarly, they include a cameo by a pair of Drake and Josh characters. One episode even has Carly and Spencer watching an episode of Drake and Josh.
 * There is a solution.. possibly. See Dan Schneider for info. In short, there is a Show Within a Show that could be what the characters are referring to and not Drake and Josh''.
 * That solution is then torn apart by the Victorious episode Who Did It To Trina, where they explicitly state that Drake and Josh is a TV show. Even though the episode before it had Helen, one of the main characters from Drake and Josh appear and reference characters from Drake and Josh.
 * In The Office, toward the end of the fifth season, in a rare instance where two people are talking to the camera, Pam and Jim are talking about how Andy and Angela had been engaged for a couple of years, but then said that the timeline was complicated.
 * Kamen Rider OOO ' s appearance in Kamen Rider Double ' s movie and their crossover movie Movie War Core has... issues with the TV series continuity. Whilst this would not be a problem for Kamen Rider traditionally (what with each Heisei Rider series being self-contained pre-Kamen Rider Decade) the fact that Double's canon is very tight creates these problems. Examples include Gotou becoming Birth (his not getting to be Birth is a major part of his character arc) and OOO's medal count (he switches between forms he never had all the medals for at the same time at any point in the series.)
 * And Giru existing. In the series, Giru is  Also, there were Out Of Character Moments with the OOO crew, as all the details of the series hadn't been finalized when the movie was produced. This results in a movie that is clearly a direct continuation of Double but just as clearly can't be in continuity for OOO.
 * There have been three seasons of Power Rangers that have shown variations on the future: Power Rangers SPD (2025), Power Rangers Time Force (3000), and Power Rangers RPM (late 21st century at the earliest). Trying to fit them together can be problematic, especially since the various showrunners are unclear on whether or not RPM is an Alternate Continuity (although Venjix's apocalypse would explain the wastelands outside the Time-Force-governed utopia). However, there will be an inevitable Canon Welding, since everything is going to be forced together if they adapt Kaizoku Sentai Gokaiger. (Of course, it's not too hard to weld together the three seasons even without Gokaiger. The biggest bone of contention about SPD revolves around the amount of aliens living on Earth which had disappeared before the chronologically later seasons. It's not a huge stretch to assume that by the time of RPM and Time Force, the aliens have become Human Aliens by either adapting to Earth's atmosphere or integrating with humans.)
 * The Power Rangers Samurai team-up "Clash of the Red Rangers" offically shoved RPM into an Alternate Continuity by saying RPM took place in another dimension. However, doing that creates other continuity problems, namely in one episode Tenaya is seen picking up an Operation Overdrive helmet, which means you would have to shove Overdrive in with RPM, which creates other huge problems thanks to "Once a Ranger."
 * In "Alpha's Magical Christmas", a direct-to-video musical released during the second season of Mighty Morphin Power Rangers has many continuity errors such as the team already being acquainted with Rocky, Adam and Aisha, even though Tommy is still wearing his Green Ranger costume and not the White Ranger one, while Jason, Zack and Trini are "at the Peace Conference", even though they're still Rangers.
 * Frasier Crane famously told his friends at Cheers that his father was a research scientist and had died years before. This was Handwaved in his Spin-Off series Frasier as having been something he said because he was angry at his dad that day, but it was in fact not something that was said once; his characterizations of his father and his identifying himself as an orphan took place consistently over quite some time during his years in Boston.

Oral Tradition, Folklore, Myth and Legend

 * Who is King Arthur's greatest knight: Sir Gawain, Sir Lancelot, Sir Percival, Sir Galahad, or King Pellinore? Did you even know that in many of the earliest tales, it is Sir Gawain, without question? (And before that, it was Mordred as a good guy.)
 * And what about Sir Griflet? Originally one of Arthur's most loyal knights, he was pretty much supplanted by Sir Bedivere.
 * And Lancelot, the one knight that everyone knows, isn't even part of the "original cast". He was originally the star of his own set of adventures and only got mixed in with the other knights along the way. Along the way he went from a mentally-unstable berserker built like a barrel on short legs to Prince Charming.
 * According to Peter David, Lancelot was "the first Mary Sue." This certainly explains his (or rather his reincarnation's) treatment in his novel Knight Life.
 * And Morgan Le Fey went from being a benevolent sorceress who had saved Arthur's life on multiple occasions to a vindictive Yandere bent on breaking up Arthur/Guinevere to the mother of the Big Bad to the Big Bad herself. And even after Mordred was retconned into being her son, he originally wasn't by Arthur. And then the whole Brother-Sister Incest thing got added in.
 * And along came Kinoko Nasu. Isn't this a twist of Fate? Excuse the Incredibly Lame Pun there.
 * Modern writers who try to keep things relatively sane while using many, many sources for Arthurian myth use this sequence: Gawain was one of Arthur's best friends, probably one of the first Knights of the Round Table, and by far the most Badass knight in Arthur's court - but he had a severe problem with losing his temper, and would end up losing to lesser knights in duels because he would get angry and clumsy, so Arthur never chose him to be his Second in Command; Lancelot was the Champion Arthur had been looking for to sit at his left hand, because he was more level-headed than Gawain and nearly as skilled - problem is, the guy was a little too interested in Guinevere, and we all know where that led; Galahad, the son of Lancelot, became Arthur's second and final Champion, who was basically as skilled as Gawain, and as level-headed and cunning as his father, making him the greatest knight to ever live - his only downside was that he was more loyal to his faith than to his king, and once the Grail showed up he and several other knights packed up and left to find it, though he did return later. Percival is considered the most noble of knights, and lived the code of chivalry to a "t," so only both he and Galahad received the Grail, but wasn't as strong as any of the other three knights, so he was never a "Champion." Mordred was never a "Champion," either; rather, he was a genius both in leadership and in battle, making him Arthur's favorite to succeed him, and so earned the seat at Arthur's right hand at the round table - but Arthur caught wind of Mordred's evil ambitions, and through any number of events (based on the author at the time), a schism formed between them (probably from Arthur's exiling of Mordred), and Arthur chose Sir Constantine to be his successor right before/during/after the Battle of Camlann. Yes, it takes this much space just to clarify 5 peoples' places in modern Arthurian myth. Continuity Snarl indeed...
 * In the very earliest stratum Cai (Kay) was easily the foremost of Arthur's warband.
 * If you look at the pantheon of any ancient civilization close enough you're bound to find these. Because of:
 * A. Different versions of the same myth by different writers
 * B. The Tangled Family Tree involved in every single polytheistic myth system.
 * C. Just plain weird theological things.
 * D. Syncretism, the practice of trying to fold other mythologies into your own. So the fertility goddess of the next island over is really your fertility goddess, or her aunt, or a despised rival that yours decapitated in a myth you just wrote for this purpose. Or the umpteen different theologies and practices lumped together in Hinduism.
 * Now Older Than Feudalism with Classical Mythology:
 * Case in point, Venus/Aphrodite's origin story. Was she the daughter of Jupiter/Zeus? Or was she born from the sea foam from when Ouranos/Uranus's testicle fell into the sea, long before Zeus was conceived?
 * Hephaestus's origin is a crazy example. Okay, so he was born when Hera gets annoyed that Zeus apparently gave birth to Athena on his own. She tries it, and she gets a very ugly baby. So she tosses it off Olympus. That baby is raised to become the greatest smith ever. He is then welcomed into the pantheon. At some time afterwards, he hits Zeus over the head with an ax while Zeus has a headache, and Zeus gives birth... to Athena. It's like that old "born in a log cabin he helped build" thing. Causality is just for mortals!
 * When Perseus was returning from his trip to decapitate Medusa, he met the Titan Atlas and asked to share his hospitality. Atlas was a jerk and refused, so Perseus turned him into a mountain with Medusa's head. Perseus' distant descendant, Heracles, later stopped by the same region, where he got the help of a completely healthy and not-at-all-stone Atlas in stealing some Golden Apples. (Keep in mind, Medusa's effect on people is incurable.)
 * Was Amaterasu conceived by Izanagi-no-Mikoto and Izanami-no-Mikoto while the latter was still alive? Or was Amaterasu the by-product of Izanagi washing himself of the filth from Yomi? The Kojiki and Nihon Shoki both say different things. And say nothing of the myth where she sends her grandson to rule over the world...

Professional Wrestling

 * The WWE's "Kane" character, whose official life story has him having been a hopelessly-insane burn victim in an asylum at the same time he was supposed to have been hanging out in college and going to parties with his sweetheart Katie. Further complicated by the storyline of his "brother", who had a whole angle where he Broke the Fourth Wall and "went out of character". The whole thing got so complicated that they had to have somebody write a book (titled Journey Into Darkness if one should want to look it up) in an attempt to explain it.
 * The Undertaker himself tends to be mildly rebooted when he gets a gimmick change. Different personas don't often directly reference older ones, but this is a double-edged sword; most glaring is when the American Badass started out with the Undertaker doing a worked shoot to sell the idea that he wasn't supernatural in character as well as out, so he could come back as a leather-clad biker, only for Kane to kill him so he could be resurrected as undead.
 * Occasionally a reference is made to their childhood home burning down, but which brother is responsible depends on who's Heel and who's Face at the time. If they're both Face, it was an accident Paul Bearer's fault.
 * A good one was in WCW, where a masked wrestler would run out and attack people during their maches. He was eventually revealed to be Rick Steiner. The problem was that the week before said masked wrestler attacked...Rick Steiner.
 * Well, of course. Rick needed a Red Herring.
 * WCWs Black Scorpion was allegedly someone out of Sting's past. It was going to be the Ultimate Warrior, but there was a small problem-Warrior didn't work for WCW at the time. After months of waiting, and literally dozens of people showing up under the mask, they finally made Ric Flair the "real" Black Scorpion.
 * The kicker? The Black Scorpion was created to give Sting an opponent other than Ric Flair.

Tabletop Games

 * Warhammer 40,000. The setting is deliberately designed to take into account the possibility of Continuity Snarl by making the tech naturally variable and everything told is either from skewed viewpoints, propaganda, or possibly inaccurate documents, reports, or histories. Its creators' pronouncement is "Everything written about 40k is canon, but it isn't necessarily true.
 * Fortunately, trying to keep up with the plot isn't really the point.
 * Even then, the adaptations manage to break it when someone toesn't bother to check the basic premises. Such as... Emperor-class battleships don't launch Space Marine drop pods, and that was probably close to two full chapters they just flung out there. It does carry 8 squadrons of small craft. The number of actual vehicles depends on the craft size, and if we are to believe Battlefleet Koronus, this translates to 160 Fury Interceptors or 320 Lightnings - since the drop pods are even smaller, it's feasible that it could carry, say, 640. The problem? This would clearly go far beyond simple support action, while the Astartes forces are completely separated (including their own spaceships) and are neither designed nor allowed to be integrated with other forces (such as Navy) like this.

Video Games

 * A very jarring example is Marathon Infinity: Blood Tides of Lh'owon. In the end of the second game, the Pfhor, an alien slaver race, rather than facing defeat, decide to destroy Lh'owon instead of letting the humans have time to evacuate. Their method is using a weapon that even the most powerful known force in the galaxy is afraid of. It basically causes the sun to go nova early. As Durandal points out in the last terminal, there's an old S'pht (Native race that the Pfhor enslaved) myth that the sun has a god in it capable of destroying the universe, but that doesn't matter much, as the Pfhor army and navy occupying the planet are destroyed. Cue Marathon Infinity, where almost none of the events summed up in the final screen of Marathon 2, such as the ultimate destruction of the Pfhor, disappearance of Durandal, and evacuation of Lh'owon happened. In fact, the only thing that is even referenced is the final terminal. The god turns out to be an Eldritch Abomination, and the player has to find a way to stop him from being released.
 * It should be noted that the continuity snarl of Infinity was deliberate.
 * While the individual Klonoa games have decent plotlines, the inter-game continuity gets rather ridiculous. In Door to Phantomile, Huepow, and , both of which are ignored when he reappears in later games. Not only does Joka have a different personality in every game he appears in, but he already knows Klonoa in half of them, and is killed in the other half. And Chipple, a random villager from Empire of Dreams, showed up in Dream Champ Tournament, where he had become Klonoa's close friend... and a kangaroo.
 * Obvious explanation: the games are all Alternate Universes to each other.
 * With the obvious exceptions of Door to Phantomile and Lunatea's Veil, which take place in the same universe.
 * It's possible the intro to Lunatea's Veil is an attempt to Hand Wave this, since
 * The Legend of Zelda continuity is inherently very confusing for the simple reason that for a long time, we didn't have the whole picture, and, of the bits and pieces we do get, we aren't told how they fit together, or how many wholes they comprise, leading to literally decades of debate as to how to organize our snapshots into Hyrulean History. Things were finally sorted out in late 2011 with the revelation of the official timeline, but the confusion will live anew each and every time a new game is released.
 * Mortal Kombat. Each character gets his/her own ending, they often intersect, with other character's endings, and are often in direct conflict with other character's endings, showing one character winning a battle in his own ending, but being killed in the same battle by his opponent in his opponent's endings. Background information in the next game says which endings are canon, and which aren't. The official word on the Mortal Kombat: Deception endings are only on Armageddon's website: Basically, Shujinko and Nightwolf's endings worked together to end Onaga. For the Mortal Kombat Armageddon endings, replace "Background information in the next game" with "Opening cutscene in the next game": Basically, either the backfiring of Taven's plan to Kill'Em All empowering everyone instead allowed Shao Kahn to win, or Kahn just flat out won on his own through his sheer power.
 * There are more straight examples of snarls in the actual story, mostly the result of the lead writer shift after MK4 . The two which stand out the most are Scorpion's oath to protect Sub-Zero (started in his MK2 ending, supported in the official comic and UMK3 ending, then ignored completely in MK4, with following games being ambiguous about the whole ordeal, or portraying him as an Ax Crazy revenge-seeker), and Kintaro's fate after MK2 (with 3 different sources, all of debatable canonicity, stating different and contradicting fates for the Shokan).
 * Another big snarl is that at the end of MK2, Shao Kahn is Killed Off for Real, but in 3 he returns alive and well to take over the world.
 * Fallout 3's last DLC was Mothership Zeta. Shortly after it's release, anybody who enjoyed the old game fluff immediately shouted BS. The whole DLC is based on an encounter from Fallout 1, one that is widely considered non-canon because of it's humorous tone. And later, it's hinted, which completely ignores various other, more serious, explanations for the war. Not to mention the DLC was very linear, which contrasted with the more open environments of Point Lookout and Broken Steel. Aliens were never confirmed canonically. They were hinted at, and used as jokes, but never confirmed. The closest we get is the American supercomputer from before stating it was based on alien technology, and saying it may be lying through it's teeth the very next second.
 * Skullgirls may count, though that the creators said that each ending is canon in some way. Still confusing, though.
 * Street Fighter. Street Fighter, Street Fighter, Street Fighter. In fairness, a lot of it is because 2 become an iconic landmark revolutionary sea-changing event of events which changed the universe forever and ever (to the point where pretty much everyone got plain sick of it). If this weren't the case, Capcom probably would've just relished their success and quietly released Alpha as a fun, inconsequential one-off featuring the unselectable fighters in the first game, then made a full break with III. As it is, II and its continuity has reach such an enormous Shuma-Gorathian level that it's dragged the rest of the Street Fighter universe into it. Hence, Street Fighter IV. With Makoto, Dudley, and Ibuki (and now Yun and Yang) at the same age and with the same motivations as in a game that canonically isn't supposed to happen for at least another three years. With a hopelessly convoluted plot involving M. Bison (who does die for real at some point, we just don't know when) and a Korean hellion we've never even heard about before. With Adon seemingly stuck in the distant past. With Rose around for no apparent reason. Before, there would be retcons; now, Capcom isn't even trying to hash it out anymore.
 * Capcom plays so fast and loose with continuity that now we have Ingrid, a character who deals with continuity snarls. Maybe. Between having few appearances and Capcom's refusal to ever clear anything up, she's more likely to turn into a snarl herself.
 * Myst created an interesting continuity snarl when it retconned the prison books of Myst I and Riven into actual ages. That is, the books themselves were not intrinsically special or different from other linking books. Myst IV goes into great detail as to what the Red and Blue ages (named Spire and Haven) are like. While this works for Myst I, it violates the events as they unfold in Riven. To beat Riven, you have to trap Ghen in a prison book. This book was presented as a special "one man prison" book, which is a very important plot point. Ghen's no fool; he isn't going to go into any random book some guy brings him. To ensure it's safe, he asks you to go through the book first. This works out in the end because it is a one man prison; when he comes through the book after you, you are freed and he is trapped. If that book were a regular linking book, you'd be trapped with a very pissed-off Ghen... who had the sense to bring a gun.
 * This can best be resolved if Atrus made the Red and Blue Trap books out of Linking Books to Spire and Haven, altering their text to trap users in the conduit between worlds. At the end of Myst, he could've simply repaired those alterations, shunting his sons onward into their respective Ages for safekeeping. The book that traps Gehn could've been a similar device, with its window adjusted so it wouldn't show the Stranger in the conduit, as the Red and Blue books had shown the brothers. Apart from minor references in the Spire and Haven journals, which could be attributed to deception or simple error by two stir-crazy captives, this resolves everything about the Trap Book/Prison Age quandry.
 * Not really; both Sirrus and Achenar clearly didn't realize they were trapped when arriving on Spire and Haven, which they would have realized sooner if the "Atrus repaired the link" explanation is true.
 * The official version is that that the "real" Stranger talked his (or her) way out of it, which the player can't really do.
 * It isn't the only retcon in the game's canon that poses problems for Myst. When the official rules for linking books were more clearly established, they included the fact that sound doesn't travel through a linking panel. This means that the stranger couldn't have talked to Sirrus and Achenar, regardless of whether they were in prison books or prison ages, nor could he have talked to . This is compounded by the fact that Sirrus, Achenar and definitely shouldn't have been able to see the stranger, as although the linking panel lets you see an Age, you clearly can't see back through a linking panel even inside Myst.
 * Mega Man X was supposed to end after X5, but didn't, leaving a complicated mess of the continuity of its series. Maybe it's just because some of those games don't exist for some people.
 * It's really not that complicated: After X5, two timelines were created. One continues to X6, X7, Command Mission, and X8. The other continues to the Zero series, and proceeds beyond that to the ZX series.
 * Except for that Word of God states that the Jakob Elevator from X8 eventually becomes Neo Arcadia from the Zero series, and Zero's ending in X6 is the last event in the X timeline before the Elf Wars and Zero. While Executive Meddling did cause Keiji Inafune to rework his ideas for the Zero series, it's made blatantly clear that the following games are indeed canon, whether some people like it or not.
 * Each installment of The Elder Scrolls is made by a different team, and each has a very large amount of information in each game. Later teams have been known to completely overwrite what was established by earlier teams. Every single installment has a portion of the fanbase that declares "They Changed It, Now It Sucks".
 * The Elder Scrolls series even has an in-universe continuity snarl: the Warp in the West. Somehow, all of the contradictory endings of Daggerfall are true.
 * Touhou Project: Did the first five games happen, or are they a separate continuity altogether? Are the PC-98 versions of Reimu and Marisa the same characters as the Windows versions? What exactly is Alice's backstory? And where in the world is Mima?
 * Those specific examples are only a problem if you assume the PC-98 games are still in continuity. Though the Windows games have a number of minor details that appear to contradict each other.
 * The Blaze/Silver/Nega issue in the Sonic the Hedgehog series. In Sonic Rush Series, Blaze is from an alternate dimension. In Sonic '06 she is from the future (and seems out of character). Additionally, due to that fact she was from the future, she could be REAL version of Blaze, who isn't born until later. The other one DID come from an alternate universe...
 * Later on, in the DS version of Colors (which may or may not be canon), Blaze appears alongside Silver during the third mission on Sweet Mountain with hints that these two have worked together in the past, making this most likely the '06 Blaze (who was Silver's best friend).
 * And then there is Generations. Blaze is first seen at Sonic's birthday party interacting with Cream and her in-game character profile notes that she's from another dimension, indicating that this is the same Blaze from Rush. As a Continuity Nod (of sorts) to 06, Blaze is found in Crisis City. Here's where things get wonky. After Sonic completes the Crisis City Act 2 mission "Blaze: Piercing the Flames", Blaze will remark, "I never thought I'd find myself in Crisis City again," bringing up the question of how exactly Blaze knew of a place that a) another version of herself visited and b)' existed in a timeline that was erased from history.
 * It was NEVER stated that the Rush and Sonic 2006 Blazes are alternate universe versions of the character, that was merely a fan theory. Not that this makes things any less confusing.
 * Additionally, both Silver and Eggman Nega (characters with prominent ties to Blaze, but connected to her by different games) are drawn into this snarl as well, as the two appear in the Rivals series--sans Blaze. Here, Silver is still from the future, but Nega (established in Rush as Eggman's parallel self from the same dimension Blaze is from) is now a descendant of Eggman, embittered by how Eggman's failures have tarnished the family name in the future and is now an enemy of Eggman instead of working with him. Later on, Nega reappears in Rush Adventure and Rivals 2 with the conflicting backstories of his appearances between Rush and Rivals. It's implied that (due to '06 slamming down on the Reset Button until it cracked) Silver now hails from the Rivals future and Blaze is from Rush (with no official word on Nega with his lack of appearances since), but Silver is still the Rival Battle for the Modern era of Generations (which takes place in Crisis City, no less) and
 * The Nintendo DS Updated Rerelease of Phoenix Wright: Ace Attorney featured an extra, fifth case which takes place in between Ace Attorney and Justice For All  wherein Phoenix and Edgeworth work together to assist Ema and Lana Skye in their legal case. However, when Edgeworth reappears in Justice For All's fourth and final case, Phoenix claims not to have seen him since   and Edgeworth supports this by claiming to have left the country right after said events; neither of them seeming to remember their work together on the Skye trial. This could simply be explained away as a case of Canon Discontinuity by stating that the fifth case of Ace Attorney never really happened in the series proper, due to it being an addition for the remake. But, Ema is integrated with the official continuity in the Apollo Justice arc by having her appear and explain Wright's involvement with her sister's case, thus making Phoenix's and Edgeworth's reactions to each other in Justice for All seem odd in retrospect.
 * It's quite easy to make it fit in canon if you ignore the one part where Phoenix says he has not seen him since  and just consider that they were really referring to case 5 of the first game rather than case 4 (case 5 actually does somewhat set up Miles' disappearance). This problem was basically made due to bad porting. If they changed the background in Phoenix's little "Haven't seen him since" monologue, this whole problem would have never existed.
 * What's really weird is, because of the order the games were released in overseas, the translations had every chance to fix this and write it so that no one would notice the problem, and they... didn't.
 * Ironically, Super Robot Wars is pretty successful at averting this. In fact, Banpresto does the exact opposite of snarling continuity up and instead snarls it together. At the point, the original games, Alpha, and Original Generation have several common ties, thanks be to several characters who can time or dimension travel (Shu, Ingram, and Gilliam head the list).
 * Odder still when you realize that each was originally in its own canon, and these characters were only giving out Continuity Nods. Original Generation is in the position currently of tying the original games/Alpha/MX/The Great Battle/Hero Senki/etc into one interlocking whole courtesy of characters who in canon reference their own appearances in those canons.
 * The creators of World of Warcraft, after admitting they had forgotten a key fact about the eredar that was established in Warcraft III's manual, went on to say that they didn't care about continuity as much as making a good game and brushed off complaints about the changes made to the draenei. Eventually, fans learned to ignore this and some other minor retcons.
 * The draenei retcon was fairly minor in terms of effects to storyline (the draenei didn't have much involvement in it before), although it did retcon the background of Sargeras somewhat (to make matters confusing there are actually two new explanations for his corruption, one being the same as the old one but with the eredar replaced with demons in general, and the other being that he just came to perceive the universe as flawed, with no mention of demonic corruption. Nobody is quite sure which is canon, although the evidence would lean towards the latter one).
 * The real Snarl (which was thankfully sorted out) was the origin of Garona, a half-orc and a fairly important figure in lore. She originally had orc and human parentage, and was born before the orcs launched their first major invasion (originally there was quite a bit of time between the opening of the Dark Portal and the First War, during which the orcs mainly did small raids on the human settlements nearby the Portal). However when the First War was retconned to have happened almost immediately after the opening of the Portal, there was no way for her to be half-human. Her parentage went unexplained for years and for some time it seemed that she was simply going to be erased from continuity, but she was finally given a new origin, making her a product of the warlock Gul'dan's experiments that involved breeding draenei prisoners with orcs, and then making them grow rapidly into maturity with magic.
 * Blizzard recently introduced a new one with their whole "There must always be a Lich King" thing, although they still have time to justify it. The idea is that if no one takes over the job as Lich King, then the Scourge will overrun the world and destroy everything. There's two problems with that. One: There can't be that many Scourge left, since we've fought and destroyed them all the way to the Lich King's very doorstep. Two: We've already seen what happened when the Lich King loses power without a successor, it was the entire plot of the Warcraft III expansion, the Frozen Throne. The Lich King was dying due to a spell that Illidan cast, but he was interrupted before he could finish. As Arthas rushed over to Northrend to take over, the Scourge did not overrun the world. In fact, they started to become the Forsaken, who are supposed to have their minds back. Thus, if we assume that the new revelation is true, it not only makes Illidan look like a big fool (even bigger than the heroes who trusted Maiev), it implies that the Forsaken are an evil more dangerous than the Scourge. Although the Wrathgate event and subsequent invasion of Undercity make this a very good possibility, the Forsaken are a playable race and it seems doubtful that the game will ever truly confront or resolve this problem.
 * Possibility, it might actually have to do with the Elder Gods, which the Nerubians used basically live over, and the Lich King might technically be accidentally keeping it sealed. Scourge boosted by the power of Eldritch Abominations might be....bad. Very Bad.
 * Considering that Yogg-Saron, god of death, very loudly screams about how the Lich King is trying to usurp his throne, this seems like the most likely explanation. Note that Yoggy was still sealed when the Forsaken were freed, which explains why they kept their minds instead of being re-enslaved by him.
 * Blizzard lampshaded their tendency to do this with the Well of Eternity dungeon, which revisits a previously established moment in Warcraft lore using time travel. Defeating the Dual Boss at the end in the wrong order grants the achievement "That's Not Canon!"
 * The continuity of Persona titles can in fact be taken as all games being in the same universe, despite great differences between the first 3 games(actually 2, but one is a two-parter) and the newer 2. This is because both games in the aformentioned two-parter, Persona 2, end with a massive Cosmic Retcon, the second of which may have reset everything from the first game as well. The third also tries to end itself by retconning out it's own existence, but this time, the protagonists see through it(though it is still a Downer Ending). This is made even more confusing by the fact that the later games make several Shout Outs to the earlier games in the forms of former playable characters being mentioned on TV or by other characters. In addition, the nature of the enemies and of the Personas which the game is named for do not remain consistent, with the first two games featuring demons from the main series, while the latter two feature shadows born of the human psyche, which is what Personas from the first two games were. Even the portrayal of shadows is inconsistent in the newer games, which definitely share the same universe, as P3 has artificially made shadows, where as P4 has more "natural" shadows.
 * There isn't really that much inconsistency; the only artifical shadows are the Full Moon bosses and Strega's Personae. While it is true that the bulk of the shadows in 3 are tiny fractions of Nyx's essence while in 4 they are reflections of human emotions and thoughts, Nyx (Mankind's subconscious wish for death or an escape from pain) herself, along with  have their ultimate origins as reflections of emotions just like in 4. Of course, 4 also has  ; who doesn't appear to have either of them as her origin.
 * The Halo universe can't make up its mind on whether there was a single "class" of Spartan-IIs or more. Summed up at this Wikia Wikianswers page. This relates to the question of how many Spartans there were.
 * As the series continues and more extended universe books are printed, this is steadily getting worse, most egregiously with the background of the Flood, the Battle of Reach and the events leading up to it, and Humanity's relation with the Forerunners- is Humanity
 * The first Street Fighter Alpha basically treated the SNES Final Fight sequel, Final Fight 2, as if it never happened. They did so by introducing Zeku as Guy's Bushin Ryu predecessor, ignoring the fact that Genryusai from Final Fight 2 was precisely introduced to fill that role. The Alpha series continued with no reference to Genryusai's existence until Maki, Genryusai's daughter and a fellow Bushin apprentice, was introduced to the portable versions of Alpha 3, where she was Zeku's other student. The developers didn't bother to explain where Genryusai fits in within the Bushin Ryu hierarchy, but some fans have postulated the idea that Zeku was actually Genryusai's student.
 * While early Pokémon games' differences between "Generation" versions are mostly aesthetic, later years significantly change the plot and in Pokémon Ruby and Sapphire's case, who the main antagonist is. Then there's whether the pre-Game Boy Advance era games are canon, or if only the remakes are.
 * Continuity in Pokemon games is usually thought of as being based on how the Pokémon themselves are traded from game to game, but this can get a bit confusing when you factor in Pokémon Colosseum and its sequel, Pokémon XD. The later takes place five years after the former, but both games are only compatible with the GBA games, which are assumed to take place at the same time. The DS games (The Sinnoh-based games and Johto-based remakes) take place four years after the GBA games (The Hoenn-based games and Kanto-based remakes).
 * The Nasuverse has an interesting approach to continuity snarls.
 * The first comes into place with Kagetsu Tohya, a sequel for Tsukihime. Kagetsu Tohya takes place in a dream world where the continuity is heavily blended and mutually conflicting events all take place together. For example, whether or not Akiha goes to Shiki's school depends on what he is thinking that morning. However, it should be impossible for this to be possible at all because the story is based around Len, and there is no route in Tsukihime where Shiki meets Len (Arcueid's familiar at the time) while Akiha goes to school with him. The continuity snarl occasionally confuses Shiki as well, but he's prevented from really thinking about it by Len.
 * An equally weird example makes up the plot of Fate/hollow ataraxia, which blends the timeline for Fate/stay night. See, the nature of FSN means that almost the entire cast has to be killed off before the end, but they're all okay again in FHA. Characters who died in all three routes are back.
 * Finally, Ryougi Shiki appears in Melty Blood despite word of god stating that she and Tohno Shiki do not share a universe because the odds of two people having the Mystis Eyes of Death Perception at any given time make it impossible. Nobody seems to have had the eyes for several thousand years, meaning the odds of having them manifest are at probably trillions to one. Melty Blood has other issues than this, however. Satsuki is alive and a vampire, Arcueid is still around but not all yandere-y, Kohaku's route appears to have been partially resolved, Vermillion Akiha etc.
 * At least in Ryougi's case, she is explicitly stated to come from a different universe, as Kara no Kyoukai is set in an alternate reality from Tsukihime and Fate/stay night.
 * Okami may only be a 2-game series, but it has one thing it can't agree with itself on. Okamiden introduces a Akuro, who is the Big Bad of the game. Now, dialogue when he's introduced heavily implies that he is the successor of the previous game's Big Bad, Yami. But later, the Knowing Jewel claims that he merely used Yami as a vessel. Keep in mind that Akuro didn't exist in the first game, and that both of these versions of what Akuro is come from the same game! Jeez!

Web Comics

 * Drowtales' rolling Retcon (repeatedly sequentially updating older chapters with new art and story) causes chaos for many fans' understanding of the comic's backstory, and there are ongoing debates on the forums as to what formerly canon information is current canon and what isn't.
 * The Order of the Stick parodies this trope with an actual entity called The Snarl; created when multiple Gods tried to create the universe and had disagreements about how things worked.

Web Original

 * Whateley Universe: Does the magic department offer introductory classes for people with no previous magical ability? In one story, a magically inclined member of the school board (who, presumably, would know) explicitly says no. And yet, Ayla will be studying magic for the first time in the spring.
 * A partial answer now exists: You need to be able to gather the energies of Magic in some way to take the courses in Magic (and it's explicitly noted that there are (inefficient) ways a normal human can do so).
 * But that still doesn't really work - in There's an Angel in Dickenson Cottage Lodgerman explicitly tells Kerry that her brother can't come to Whateley despite his enormous magical potential because Whateley only trains students who can already use magic. Ayla can't do this, but is somehow getting enrolled in a Magic 101 course anyway. Lodgerman may be lying for some reason or another, of course, but it isn't addressed.
 * Homestar Runner is full of this. Strong Bad meets characters from Shows Within The Show whom HE HIMSELF MADE UP.
 * Any attempt to create a consistent origin for Dr. Insano creates an awful one of these, mostly because there is no effort made to keep things in the slightest consistent. The That Guy With The Glasses site now features an attempt to explain his existence, which will probably be made inaccurate next time he shows up.
 * Amusingly, Spoony's explanation for him is "There is no continuity, there is only Insano."

Western Animation
"Roger: My name is Braff Zacklin. I was an international race car driver. One day, a baby carriage rolled out onto the track so I swerved into the retaining wall to avoid it. The car burst into flames, but the baby miraculously survived ... I was that baby. Steve: That doesn't make any sense. Roger: I'm Braff Zacklin!"
 * For all that's said about the inconsistencies between the Unicron Trilogy of the Transformers franchise (Armada, Energon, and Cybertron), the main, original, Transformers time-line is even worse. There starts out with two distinct main branches, the original comic and animated series, but then along comes Beast Wars and Beast Machines that uses elements from both series simultaneously. Add that to the splintering off done by the Dreamwave ongoing series, and you just have to wonder how all of these things could possibly co-exist together.
 * The aforementioned series? In Japan, Cybertron is Galaxy Force, and it appears it's unrelated to its Japanese predecessors, Micron Legend and Superlink. The US version tries to tie the two together, but there are still some problems, so a comic was produced that chalked all of this up to a big warp in time and space... even though some minor retcons and a few lines of explanation saying where the older characters might have gone to would have sufficed. Yeah, it wouldn't have been perfect, but come on, was it really necessary... especially since they've already let the original timeline rage out of control?
 * Worse, the show itself mentions none of this, and we're left with plot holes big enough for Unicron to fly through. The biggest example is this: when Optimus and Leobreaker first combine, everyone is in total and absolute shock at the impossible - robots combining - happening. Guess what the main gimmick of both Armada and Energon was? (Hint: In Japan, Energon was called Super Link.)
 * Oh, it gets worse: Takara has now decided that Galaxy Force is in continuity with Micron Legend and Superlink, just as Cybertron is in continuity with Armada and Energon. (It should be noted, however, that many characters in Galaxy Force do not share names with anyone in Micron Legend and Super Link, whereas Cybertron, in a manner similar to Robots in Disguise, named many characters after familiar ones. This makes the Japanese Continuity Snarl and the American one different - sharing The Verse doesn't make single characters out of the Micron Legend and Super Link characters and whoever in Galaxy Force they most resemble.
 * What makes it worse is that it suffers from Xorneto syndrome (see X-Men example) in that the right hand seems to not know what the left hand is doing. All of the Unicron Trilogy's continuity problems could be solved with the "black hole's effect on the multiverse makes Cybertron the Post-Crisis version of The Verse" statement... but that didn't stop everyone with the ability to create official material from explaining their own pet peeve a different way, explaining some things that didn't need explaining, and making the bigger problems all the more glaring.
 * The Japanese G1 time-line also considers the 2007 film and seemingly unconnected series Car Robots (aka Robots in Disguise) as part of the original continuity. Try to make sense of THAT.
 * Oh, yeah, and Transformers Animated? That one that took place in the 22nd century, made the Autobots virtual celebrities on Earth, had a completely different style and design aesthetic, included superheroes, genetic experiments Gone Horribly Wrong, and robots being so commonplace that they were used to teach, and ? In Japanese continuity, it's a prequel to the live-action film.
 * Furthermore, some characters are "multiversal singularities", meaning that every incarnation of a certain character (Like, say, The Fallen) is the same being, instead of just some alternate version. This leads to some headache inducing retcons among other things.
 * This gets worse with Alpha Trion, who was recently retconned into being one of these. After a Mirror Universe lunatic version of the character was introduced in Transformers: Shattered Glass.
 * The latest incarnation of the Transformers mythos is still neonatal (a couple of months old as of this writing), and it's already turning into a Continuity Snarl. According to the powers that be, the video game Transformers: War for Cybertron, the novel Exodus, and the upcoming TV series Transformers Prime are all part of the same continuity. The problem is, the plots for Exodus and War for Cybertron are so disparate and contradictory as to be completely incompatible. Time will tell whether the Prime cartoon will make any attempt to address these discrepancies, or whether it will quietly sweep them under the rug and ignore them, and encourage the fans to do the same.
 * Later statements by Hasbro have clarified that War For Cybertron, Exodus, and Prime are part of the same continuity in the same way that the original Transformers cartoon and the Marvel, Dreamwave, and IDW comics are all part of the G1 continuity—IE, they share similarities in aesthetics and characterization, but are not necessarily consistent with one another. The fandom generally uses the term "continuity family" to refer to such an arrangement, and this difference in terminology is part of the reason some fans continue to grumble about discrepancies in canon between the three works.
 * The upcoming sequel to War For Cybertron may just complicate things further.
 * Played for laughs on American Dad when Roger explains the background of a character he's made up for himself:


 * Star Wars: The Clone Wars begins to run into this during the third season. All of the episodes take place in Anachronic Order, making their placement already difficult. Some even Retcon the timeline for past episodes. For example, events in one episode took place in between the two prior season finales...and implied the second season finale took place before the first.
 * It doesn't help that the series itself is retconning a fair amount of older series's, such as many of the Republic Commando novels.
 * Not to mention killing off a Jedi Master in the middle of the Clone Wars who explicitly was still alive after the war ended.
 * Care Bears Movie II: A New Generation does this to previous works in the Care Bears franchise, from having the Care Bear Cousins grow up with the rest of the Care Bears, instead of separately in The Care Bears Movie.

Real Life

 * Trying to keep track of everything that happened after the death of Alexander of Macedon (aka the Great) is almost impossible for anyone, even those with higher degrees in Classical History. The scale of the political maneuvering between his putative successors is too large to summarize. Suffice to say that one Classical Historian has described the carnage and politics between Macedon, Persia, the Ptolomaic Empire, and all the others, as a 'Macedonian Soap Opera'.
 * Similarly, the Mexican Revolution. Once the United States got involved, it gets even more confusing because the Taft and Wilson administrations supported opposite sides of the conflict. And this is leaving out historilogical debates over the whole mess.
 * The Schleswig–Holstein question. Lord Palmerston is said to have remarked of it, "Only three people have ever really understood the Schleswig-Holstein business — the Prince Consort, who is dead, a German professor, who has gone mad, and I, who have forgotten all about it."
 * As a result of a Gambit Pileup that's been going on for centuries.
 * Any time a city has two teams with the same name at different times, it can lead to this. A good example in the National Hockey League: from 1971 to 1996 there was a team called Winnipeg Jets, who has since moved to Arizona as the Phoenix Coyotes. In 2012, the Atlanta Thrashers moved to Canada, where they were rechristened... Winnipeg Jets!