Retcon / Live-Action TV

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• The most painful, quickest retcon ever was in The 4400. One episode revolves around re-opening the 4400 center. Notably, police try to stop it and tell Shawn he can't heal anyone, because no one can use 4400 abilities, whether they were a 4400 or got it via promicin injection. The very next episode features someone saying "Maia is a 4400, she can legally use her ability". The show then kept on like that without even acknowledging that superhuman abilities were entirely banned in the first few episodes of its last season.
• Alias: "Hey you know the man you loved that died and you grieved over? Yeah, now he's alive remember, and we totally knew about it all the time, even though you cried lots in private over his loss." Explainable in-universe, however, since the enemy is dangerous enough to be able to successfully bug even the private homes of the characters for long periods of time before being uncovered. Having experienced that in the past, it would be sensible for that kind of charade to continue in private just to be on the safe side.
• Angel had one about halfway through season four when the gang find out that Big Bad Jasmine had engineered most of the major events that brought the gang together.
  • In-universe, Angel had the gang's memories retconned to edit out Connor and allow him a normal life. Eventually, the reality alteration does get exposed, however.
  • There's a big plot point in Season Two when Angel is contemplating turning Darla back into a vampire, explaining that he's never done that before with a soul and that may make a difference. Three seasons later, a flashback episode has him turning someone into a vampire while Angel has a soul: It didn't end well, and would thus be very strange for Angel to consider.
• The Arrowverse initially started with the idea of superheroes being a new thing, superpowers didn't exist, and it was a mundane world (albeit with character with badass combat skills). Then it was revealed that no, there was superscience in the form of the mirakuru serum, which Oliver had known about. Then the particle explosion in Central City caused exposed people to have superpowers. Then it was revealed there was real magic (which Oliver had known about), superpowers that had nothing to do with the Central City explosion, and a lot of superscience, and aliens, and the government had been aware of this to the point of having their own superhero team during World War 2.
  • Within Arrow itself, Diggle originally had an It's Personal with Deadshot because Deadshot had killed Diggle's brother, which they knew because Deadshot uses a trademark kind of ammunition coated in curare poison. A few seasons later, when they decided to bring Diggle's brother into the show, it turns out that his death was faked by H.I.V.E., who had provided Deadshot with special ammunition that would allow him to be revived. So Deadshot (unaware of the whole death-faking situation) still shot him, while explicitly not using his signature ammunition, but actually did shoot him with his signature ammunition so that the authorities would know he was the shooter.
• Better Call Saul, which is a prequel and spinoff to Breaking Bad, avoids it for the most part, but has some minor cases of this.
  • One of the most noticeable is with the age of Mike's granddaughter. Arguably though, this is pretty justified owing to the need for a kid old enough to form sentences that Mike can have interactions with.
  • In Breaking Bad, Tyrus Kitt was introduced in season 4 as the person hired by Gus to monitor Walt following Victor's death. He's implied to be a new hire that Gus had brought on-board to replace Victor. Better Call Saul, on the other hand, establishes that Victor and Tyrus actually worked together back in the day before Walt was ever brought on, and were Gus's most trusted muscle. Which would certainly explain why Tyrus is so chilly and distant to Walt and Jesse during Breaking Bad: that's not his personality, he's angry at them for what happened to Victor.
  • Mike only worked with Gus for about seven or eight years, not 15+ as Breaking Bad might lead you to think.
  • While retaining Saul's law school alma mater of the University of American Samoa from Breaking Bad, a closer look at the degree on Saul's wall in that series reveals he graduated in May 1984, while a good chunk of the plot of Better Call Saul hinges on his only recently having become a lawyer.
  • In his first episode of Breaking Bad it's inferred that Saul Goodman only uses that name professionally as a lawyer just because it sounds Jewish, with the phonetic joke of the name ('s all good, man) being an out-of-universe gag. However in Better Call Saul it's revealed that Saul has been using the alias in his con artist days, long before ever becoming a lawyer, and fully acknowledges the "'s'all good, man" pun.
• Several in Battlestar Galactica (2003):
  • In the initial mini-series and first few episodes, humanoid Cylons are shown to have glowing spines during intercourse. However, this was officially retconned by producers when it was pointed out that Dr. Baltar already had an amazing Cylon detector. In his pants. Though note Scifi Channel commercials for the second half of season 2, which show a spinally-luminated fetus. Also, in the commentary for later webisodes, writer Jane Espenson mentions it was planned to depict Eight's spine glowing during sex with Gaeta but the scene was rewritten for them to kiss instead. The novelization of the Miniseries says the glow isn't visible to the naked eye, but that book isn't Canon.
  • In early episodes we learn that human Cylons had 'evolved' from the Centurions after the First Cylon War. Later there are a few hints that human models already existed before the war. Then, in the last ten episodes, it is revealed that the ancients on Kobol first created artificial 'humans' thousands of years ago, and descendants of these same artificial humans had worked with the Centurions to create the new human models.
  • Several characters are revealed to be Cylons and thus, alive after they and the audience thought for years they were human and/or dead. Stand up Anders, Tyrol, Tigh, Tory and Ellen!
  • In the miniseries, the audience learns that there are only twelve Cylon models that look like humans. These are gradually revealed over the series, the twelfth and final Cylon in "Sometimes A Great Notion" then, four episodes later we learn of the (former) existence of a lost thirteenth model, whom we never see.
    • This one is especially bad because when it was first revealed, many fans took it as an explanation for what the hell Starbuck was after being apparently resurrected despite her dead body still being on Earth. Ron Moore was quick to deny this, as it was just thrown in as an explanation for why the number designations for the humanoid Cylons skipped number 7.
• The Brady Bunch: Events and characters that occurred in the Brady Spin-Off The Brady Bunch Variety Hour are retconned by the time The Brady Brides make it to air; as such, none of the events in the ill-fated variety series are considered canon.
• This happens several times in The Brittas Empire:
  • The 1994 Christmas Special shows Julie working at the centre only days after it first opened in 1989. This contradicts Series 1, which had the long-lost Angie working there at the time instead.
  • Initially, Carol's twins (born in Series 2) were a boy and a girl (Tom and Emily). By series 5 however, Tom had been retconned into a girl named Jessica.
  • Also, initially, Helen and Gordon had three children, that being Jonathan, Tom, and an unnamed third child. This increases to five with the birth of Matthew and Mark at the end of Series 3. However, by "The Disappearing Act", Helen mentions only having four children, a fact which is backed up by Gordon in "Curse of the Tiger Women".
• Buffy the Vampire Slayer:
  • The show plays with and subverts this trope in a very interesting way within the show. In the end of the first episode of season 5, Buffy suddenly has a sister that has never appeared or been mentioned before, and it had previously been established that Buffy is an only child. But neither Buffy nor anyone else shows any signs that anything is out of the ordinary. It later turns out that powerful magic was involved that not only created Dawn, but also retconned her entire past life into the memories of the people of Sunnydale. Even when it turns out she didn't really exist until some months ago, she continues with her current life as if she were a regular person.
  • In season 1, Giles states that he is inexperienced with magic and has never used it before. By season 2 it has been established that while he was in college he was using magic recklessly enough to gain the nickname "Ripper" and to summon a dangerous demon that killed several other people.
  • Also with Spike's introduction. He expresses anger that Angel has gone good, saying, "You were my sire, my Yoda, man!" Angel doesn't elaborate on this at the time. Later it's seen that it was Drusilla who actually turned Spike into a vampire while Angelus was his teacher and role model. In another episode Spike outright says, "Drusilla may have made me a vampire, but you made me a monster." Joss Whedon also gave the explanation at one point that 'sire' can refer to any of the predecessors of a vampire's line and not just immediate sire.
  • Spike saying that he respected Angel. Flashbacks show that he and Angel were always at each other's throats.
  • The entire history between Angel, Spike, Drusilla, and Darla. Later revelations show that they were a foursome when Angel was re-ensouled, yet they never mention each other in the first few seasons. Darla seems ignorant of Angel's situation in the first season when she tries to convince him to join her side, and Spike likewise seems ignorant of Angel's goodness in his debut, despite later episodes showing him exposed to the good Angel.
  • Similarly, the first season has Darla trying to persuade the Master about the value of turning Angel to their side, with him admiring the prowess of Angelus, whereas a later episode revealed that he hated Angelus.
  • Both Spike and Angel had their ages changed. For Spike it happened twice. He went from "barely 200" in "School Hard", to 126 in "The Initiative", to 120 in "Fool For Love". Angel had 29 years added to his age in the episode Becoming.
  • A minor example concerning Anya's demon friend Halfrek. She was played by Kali Rocha who had appeared in another episode as Cecily, one of Spike's human love interests. In her next episode when she and Spike appeared on screen together they had Halfrek say "William?" and then the two avoided each other's gaze, implying Halfrek and Cecily to be the same person. Also Halfrek's flashback scene in "Selfless" was changed from the Renaissance to the Russian Revolution to support this. The actress herself stated that she was already a vengeance demon as 'Cecily' and was on assignment when she met Spike.
  • Throughout the series it is firmly established that Sunnydale is the center of all evil activity (thanks to the Hellmouth) and has been for a long time. However, in the first season, no one in town (including Willow, Xander and Cordelia) seem to be aware of the existence of vampires and demons until Buffy shows up. Whedon tries to cover this up by claiming that everyone in town was just ignorant and/or in denial.
  • Sunnydale also seems to grow substantially in the first three seasons. In the first season several lines of dialogue make it sound like a small-ish town. Several people comment on how there's nothing to do or see there and Buffy is able to walk everywhere in town she needs to go. Later on Sunnydale is large enough to have its own University campus and a booming downtown district.
  • The notion that vampires are Always Chaotic Evil was starting to be done away with possibly as early as season 5, but it doesn't really take off until the Season 8 comics. The bonus/supplementary issue following 25, Tales of the Vampire, involves the aftermath of a teenage boy being transformed into a vampire, and neither he nor his vampire friends even come close to acting like any of the soulless monsters in seasons 1-3 of the television series. He briefly considers killing his mom, but quickly decides against it when she reveals that she still loves him no matter what. The idea of vampires killing people for food is even thrown out the window with Harmony's in-universe television show demonstrating that they can survive on non-lethal amount of blood from people. It goes hand in hand with the increasingly Black-and-Grey Morality of the series. Other hints / retcons are dropped throughout the TV series, such as the Master in Season 1 appearing much less human that younger vampires, the Judge in Season 2 noting that vampires such as Spike and Drusilla "stink of humanity", and the introduction in Season 7 of the Turok-Han, described as "neanderthal" vampires, suggesting that the series' contemporary vampires are much diluted by humanity.
  • The season 8 comics retcon Warren's death in season 6 and reveal that Amy Madison saved him. When fans pointed out that this was strange, as the First Evil impersonated him several times^note The First Evil can only impersonate someone who has died, Joss hastily said that he had been legally dead for about a minute but Amy hadn't told him out of fear of upsetting him.
  • Up until season four Willow was shown to be secretly in love with Xander for years, falling in love with Oz and having a relationship with him for around a season and a half, and was generally shown to be interested in guys. Then abruptly within a span of few episodes she was turned into lesbian and all this history was glossed over.
• Car 54, Where Are You? broke continuity to suit the backstory of the episode probably more than any other sitcom.
• Charmed:
  • In Victor's first appearance, his actor is credited as 'Victor Halliwell'. Halliwell would later be retconned to be Patty's last name, and Victor's would be 'Bennett'.
  • The series flip-flopped on precisely when Victor and Patty split up and when he left the family. In "That 70s Episode", they are already separated before Patty even knows she's pregnant with Phoebe, which seemed to contradict "Thank You For Not Morphing", where he still appeared in a Christmas home movie when Phoebe was two. Piper also says the last meal she had with him was when she was four, when Season 5 would retcon it into him leaving the night of her fifth birthday after a demon attacked.
  • The sisters constantly had to fight the risk of exposing their magic to the public. The season 3 finale revolves around them trying to get a demon to turn back time for them to reverse this. But season 6 adds in entities called The Cleaners whose job is to fix things whenever magic is exposed. They claim they've been watching the sisters from the beginning, although it is given a hand wave with the Cleaners saying the sisters otherwise had a good track record for covering their exposure risks, suggesting they never had to intervene.^note While magic was exposed in "All Hell Breaks Loose", the ones who exposed it were Prue and Piper, and the "Forget Me...Not" highlights that the Cleaners can't erase the Charmed Ones without shifting the balance of power to evil and therefore maintain their neutrality, suggesting that the solution of resetting time while they still could was more practical.
  • The show also frequently retcons the origins of certain powers/rules/entities between their introduction and subsequent appearances. A case-by-case Early-Installment Weirdness, if you will.
    • The first mention of Leo's bosses identifies them as "a group of elder Whitelighters, called The Founders." The Founders title is immediately dropped, labeling them the Elders, and when a teenage witch is admitted into their ranks, it proves that even Elder is a Nonindicative Name and that they aren't even Whitelighters (who are regular humans who died committing an act of Good), meaning everything Leo said was wrong. The Season 9 comics would state that the Elders are "sometimes" called The Founders.
    • While it's a Warlock who first uses Blinking (Teleportation), it's stated explicitly that he must have stolen it from a witch, since that's the only way Warlocks get powers. Every subsequent appearance, Blinking is a default Warlock power, and when the sisters start Blinking, it's a sign that their alignment has been switched.
    • When retired-Whitelighter Sam uses Memory Dust on the girls, it's explained that he kept it from a previous witch charge. Later, it's a Whitelighter's tool which they're given by the Elders.
    • Barbas's first appearance states he only awakens every 1300 years on Friday the 13th. His second appearance, less than a season later, Handwaves his early return. His later recurring appearances don't even bother.
  • The dates on the family tree in "Pardon My Past" had to be retconned because of the leaps they took with logic - listing Penny's birth date as 1937, and Patty's as 1950, meaning Penny was a mother at twelve! Penny was later retconned to have been born in 1930.
  • Penny's amount of husbands is first said to have been four, and then six, and then clarified as four marriages but six engagements.
• A cross-series Retcon occurred between Cheers and Frasier.
  • In a late Cheers episode, Frasier remarks that his father is dead and was a scientist in life, two things that are clearly not true in Frasier - it was explained as being the result of Frasier and Martin's relationship being quite cold at the time.
    Sam: He also said you were a scientist.
    (Martin shoots a look at Frasier)
    Frasier: Oh, what did it matter? You were dead!
• Parodied in The Conditions Of Great Detectives when, in the final episode, Banzo finds out his family has been completely rewritten without his knowledge. Originally his estranged wife was Japanese and they had a teenage daughter, Hanako who committed suicide. His new wife wants to get back together with him and run a restaurant together, she's also blonde and non-Japanese - and their new daughter (who has another name) is a lot younger and also blonde. Banzo compares the family photograph his "new wife" gave him and compares it to the photograph of the "old family" he carries in his wallet.
• CSI: NY:
  • The series had Mac stating in the first episode that he used to sit with his wife in the hospital like he was doing with the locked-in victim. Although it could mean Claire was sick before her death and got better, it's likely that they retconned how she died on 9/11, from being pulled out of the rubble injured and dying in the hospital to her body never being found.
  • A more minor one was Clare being retconned as having auburn hair, rather than brunette like in the pictures Mac showed Reed in season 4. There are reasons for having a different actress-the writers not knowing they'd need an onscreen Claire for flashbacks and the woman in the pics possibly not being a professional actress-, but it appears the casting department still got a bit lazy.
• The most egregious retcon in 20th century American entertainment is the soap Dallas which, in order to bring a character Back from the Dead, made an entire season All Just a Dream. You'd think a Soap Opera, of all things, could figure out an easier way to bring someone back.
• Daredevil:
  • The "Nelson v. Murdock" flashbacks in season 1 get subject to this in season 2. The flashbacks to Matt and Elektra's college relationship in season 2 are said to have happened "ten years ago" and after Matt had met Foggy. Yet season 2 is implicitly set in 2015, and Matt (who is shown to be friends with Foggy at the time) only started law school with Foggy in Fall 2010.
  • In the "Nelson v. Murdock" flashbacks, Foggy suggests that Elektra was in Spanish classes with Matt, when the flashbacks of Matt and Elektra's college relationship establish that while Elektra was financially connected to the college, she wasn't actually attending classes.
• Doctor Who: Many of the most notable features of the series, such as regeneration and the Time Lords, were retconned in, often to account for some out-of-character problem.
  • The first three seasons were mostly ambiguous about the nature of the Doctor and his people, but ran on the implicit idea that they were simply a highly-advanced human society from the distant future. This would change with the Third Doctor's first story, which introduced the Time Lords' binary cardiovascular system. It has remained a consistent feature of Gallifreyan biology ever since, despite the fact it was indicated that the Doctor only had one heart in the third story of the show. An accepted explanation by fanon and books and audio is that Time Lords only gain the second heart after their first regeneration.
  • In "The Sea Devils", the Doctor points out that the cave creatures from "Doctor Who and the Silurians" should have, in fact, been named the "Eocenes" instead of the "Silurians", because of the epoch they originated from, which is the real-life author (same for both stories) correcting his earlier mistake when he was called on it after the broadcast of the first story. Unfortunately, it's highly unlikely that that they could have come from the Eocene period, either.
  • The question of whether or not the Doctor had incarnations preceding William Hartnell has been answered, retconned, re-retconned and re-re-retconned:
    • In "The Three Doctors", one of the Time Lords refers to Hartnell as "the earliest Doctor", implying that the Doctor had had no pre-Hartnell incarnations.
    • "The Brain of Morbius" attempts to retcon what had been established in "The Three Doctors"; during the mind-bending contest between the Doctor and Morbius, eight faces of apparently prior incarnations of the Doctor are shown (this was confirmed as the production team's intent by invokedWord of God).
    • These apparent prior incarnations of the Doctor were, however, not referenced again afterwards. One year later, "The Deadly Assassin" created threw a major spanner in the works by establishing that Time Lords could only regenerate twelve times. This did not directly contradict the "Morbius Doctors" interpretation, as the incumbent Tom Baker would have been the twelfth incarnation, within the limit. However, as this would have left him as the penultimate incarnation, it made a future re-retcon necessary in order to extend the life of the show beyond Baker's successor Peter Davison.
    • It was eventually re-retconned in "Mawdryn Undead", when the Doctor says "I can only regenerate twelve times. I have already done so four times." This re-retcon was backed up several more times over the following decades by lines that explicitly referred to the Hartnell incarnation as the first or to the Doctor having only as many incarnations as would be consistent with this, and of course, by the Davison Doctor successfully regenerating in "The Caves of Androzani"^note If the eight faces from "Brain of Morbius" were the Doctor's previous incarnations, this would have been the Doctor's 13th regeneration.
    • For the next 37 years, fandom squared the circle of the "Morbius Doctors" by concluding that the faces shown in "The Brain of Morbius" were in fact prior incarnations of Morbius, which did not contradict what was shown onscreen even though it hadn't been the production team's intent.
    • "The Timeless Children" re-re-retconned this by showing the Doctor as not being a Time Lord at all, having had countless pre-Hartnell incarnations (including the "Morbius Doctors") and having had their memory erased every thirteen regenerations.
  • The Doctor has blue Alien Blood in "State of Decay", but normal red blood ever before and normal red blood ever after.
  • "The Two Doctors" was an attempt by Robert Holmes to retcon the early eras of the show. The loosely canonical "Season 6B" — which claims that the Doctor wasn't regenerated at the end of "The War Games", but was sent by the Time Lords on various missions around the cosmos — is actually less insane than what Robert Holmes was planning! Holmes figured that it was impossible for the Time Lords to just lose track of a TARDIS, so in reality the Doctor had been working for them from the very beginning! This also explains why the first and second Doctors were never able to control the destination of the TARDIS. Holmes said that after the events of "The War Games" the Doctor's superiors let the Doctor take the fall for his interference, even though he had been acting on their orders.
  • "Rose": While telling off the Doctor for treating Mickey's apparent death so callously, Rose mentions that she's going to have to inform Mickey's mother that he's dead. Over a season later, in "Rise of the Cybermen", when Mickey's family history is revealed, Rose explains that he was raised by his grandmother because his father ran off and his mother "couldn't cope", with the wording and tone of voice implying she's dead and has been for some time. The 2018 novelization of "Rose" provides more detail and sticks to the later version of the Smith family history by revealing that Odessa Smith committed suicide when Mickey was around 5, and changing Rose's dialogue in the riverbank scene to have her say that she's going to have to tell his friends that he's dead.
  • "Aliens of London" has a coroner, referred to in the credits as Dr. Sato, who examines the fake pig-alien after it's brought to Albion Hospital. The actress was later cast in the spinoff Torchwood as one of the main characters, Toshiko Sato, who was not a doctor at all. Tosh's presence at the hospital was retconned as her covering for her colleague Owen, who was a doctor, because he'd had a hangover.
  • "The Sound of Drums" introduces the idea that Time Lords can psychically sense each other, which is how the Doctor is able to quickly identify the Master in the 21st century despite the fact that he'd regenerated before escaping from the end of the universe, without the Doctor, Martha and Jack seeing his new face. This ability did not exist in the classic series, with the Doctor occasionally unwittingly interacting with disguised Time Lords like the Master and the Rani while none-the-wiser, and after "The End of Time", Russell T Davies' last story as showrunner, it has never been mentioned again: Davies' successors Steven Moffat and Chris Chibnall chose to ignore the ability while introducing new incarnations of the Master, having the Doctor being unaware of their archenemy's true identity after meeting them until a dramatic reveal. (Upshot: only Ten had this ability, apparently.)
  • Uniquely, Doctor Who has had two paratextual retcons during the Tenth and Eleventh Doctor's tenures, consisting of in-universe explanations for the theme song and title.
  • "The Day of the Doctor" managed to retcon in an entire new Doctor. When it was revealed in the preceding story that a secret hidden Doctor, played by John Hurt, existed, fan theories melted down the Internet as to who he really was. Once the "The Day of the Doctor" aired, it turned out that the Hurt incarnation was the Doctor that had fought in the Time War, and committed genocide against both the Time Lords and the Daleks. This meant that every line of dialogue establishing that Christopher Eccleston's Doctor was the ninth, etc., were all lies that the Doctor was telling so that he could try and forget the version of himself that committed the heinous act.
• The series long neural-clone subplot in Farscape hadn't actually been thought of when Harvey first appears in "Crackers Don't Matter". The writers needed to think of a way to have Scorpius appear more frequently without losing his menace in the process, so decided to have him pop up as an off-kilter hallucination. It worked so well, they ran with it and started dropping hints something more was going on inside Crichton's noggin, before introducing Harvey proper later in the same season.
• Forever Knight did some retconning of the main characters' histories between the made-for-TV film and the actual television series. Nick was only about 200 years old in the film, with Janette being about 400. This means that much of their history was only conceived for the film. Kinda justified, though, since a film wouldn't have as much backstory and character development as a series would over its run.
• Friends:
  • Ross is shown in later seasons as having a long-standing passion for dinosaurs that stretches back to childhood. However, in the first season, he states he only picked paleontology as his major on a dare.
  • Flashback episodes were particularly egregious with this, resulting in the internal history that makes little sense. In the first episode, after Rachel flees from her wedding and first encounters Monica and Ross, it's implied she hasn't seen them in years, and that she and Monica were little more than casual acquaintances growing up - Monica wasn't even invited to the wedding. Later flashback episodes portrayed Monica and Rachel as practically being best friends in high school, attending prom and parties together, and Rachel spending Thanksgiving at the Geller home.
  • Also in the first episode, other than Monica and Ross, none of the other characters recognize Rachel, including Chandler. In the third season, it's revealed that Chandler had actually met Rachel just a year before her wedding, and wanted to sleep with her. Another episode reveals they had met even earlier than that, while Rachel was still in high school. Yet another episode ("The One Where the Stripper Cries") revealed that Chandler and Rachel had kissed during a college party.
  • Also, in "The One With the Prom Video", it's clear that Chandler had never seen fat Monica or pre-nose job Rachel, but in a later episode he was retconned into meeting them...and actually caused Monica to lose weight!
  • An early episode also had Rachel imply she had met Chandler at Phoebe's birthday party. Luckily, the phrasing is ambiguous enough that it could also mean she met Chandler in the first episode as was initially assumed.
  • Friends was notoriously bad at doing more harm than good with their retconning, as the episode "The One Where Chandler Can't Cry" goes to show. The entire premise of the episode was (in typical Friends fashion) exactly what it said on the tin. Only, Chandler was easily the most emotional of the boys, and had several earlier episodes revolving around this fact. He had the same thing happen with his sudden and crippling fear of dogs. The same episode that introduced Chandler's dog phobia also reveals that Ross hates ice cream... despite the fact that a past episode (The One After the Super Bowl) shows him just fine with eating it.
  • Then in "The One With The Sharks", it's brought up that Phoebe has never been in a relationship that lasted longer than a month, or lived with a partner, both of which happened at previous points in the series. While the whole living with a guy issue can be brushed off due to the fact Phoebe broke up with him after one night of living together, another episode had a boyfriend of Phoebe's mentioning that they had been together over a month. Phoebe also once mentioned near the end of the series that she had never been married before. She technically had - she married a Canadian man who she thought was gay so he could get a green card.
  • In yet another late season episode, it's suggested (through a throwaway line) that Ross got drunk and slept with the cleaning lady as a teenager. Really puts his constant whining during the first two seasons about Carol being his first and, until the start of season two, only sexual partner in a new light, doesn't it?
• In Gilmore Girls, Dean is originally introduced as having just moved from Chicago and enjoying obscure books and movies in season 1. Once he breaks up with Rory, he is retconned to be a book dumb, country bumpkin who can't imagine living in a big city after living in Stars Hollow most of his life (despite having only moved there when he was 15 and disappearing from the show when he was roughly 19) in order to draw a clearer contrast between Dean and Rory's new love interest, Jess, who recently moved to town from New York City and enjoys obscure books and movies.
• Glee:
  • Blaine was acknowledged to be a sophomore towards the end of season two and a brief appearance from an episode taking place the year before seals that, but this appearance (which takes place at the beginning of the school year) conflicts with a prior continuity about his being attacked at his old school's Sadie Hawkins dance and his subsequent transfer to Dalton Academy.
  • In season one, Tina has an awkward stutter that could explain why she feels alienated from others. After joining the glee club it disappears, which could be because singing can assist in treating stutters. She later reveals to Artie that she didn't actually have a stutter; she was faking it so Artie would like her. The real reason Tina lost her stutter probably had to do with actress Jenna Ushkowitz's portrayal. It is an inaccurate, awkward depiction and it's obvious the actress hadn't experienced a stutter (let alone met someone who had). The retcon to explain Tina never had a stutter thus glosses over the under-developed depiction.
• Good Times: The 1976-1977 season finale saw Florida marry an elderly gentleman named Carl Dixon and the two moving to Arizona (to tend to Carl's frail health condition); this was done to explain Esther Rolle's departure from the cast. When she agreed to return at the beginning of the 1978-1979 season, one of her demands was — and it was granted — that no mention of Carl ever be made, not even why he was no longer in Florida's life. (Rolle, whose Florida character was a devout Christian, said she did not want her character associated with a hardcore atheist.) Although fans often speculated about Carl's departure (death, a particularly acrimonious divorce, etc.), no mention about the Carl-Florida relationship or its end was ever made.
• Gossip Girl has done this with Chuck's parents so many times that it's hard to keep track of what is currently canon.
  • In the pilot, both his parents are alive. Then it turns out his mother died giving birth to him and his father has never forgiven him for it. Then it turns out his mother is actually alive after all. Then maybe Elizabeth Hurley is his real mom and his Uncle Jack is his real dad. After that, there was no point in trying to keep track anymore.
  • Showrunner Josh Safran really, really, really wanted people to ship Dan and Blair like he does even though Blair and Chuck are the show's Super Couple and the reason most people tune in at all. So in season five he alluded that Dan has had feelings for Blair all along and that in season one he was the only one who went to her (previously never mentioned) essay contest to support her. Never mind the fact that Blair and Dan hated each other until mid season four. Or that the episode that takes place a week after the supposed essay contest has Dan wondering if it's worth dating Serena (the girl he had been in love with for ages) because he's not sure he likes what it says about her that she can stand to be friends with a person as awful as Blair. Most of the fandom refuses to acknowledge that the essay contest ever happened since it doesn't fit in at all with what was going on in season one.
  • Safran took it even further in his interviews where he retconned so much stuff you wonder if he ever actually watched the show himself. A particularly glaring example is when he claimed Blair was never friends with Nate or Chuck. Even though the close friendship between the three of them and Serena is one of the key elements of the show.
• In H₂O: Just Add Water, the human girls-turned-mermaids frequently swim around Mako Island, and spend quite a lot of time in the Moon Pool underneath the volcano. In Mako Mermaids: An H₂O Adventure, it's revealed that a pod of natural-born mermaids live around the island and spend quite a bit of time in the Moon Pool themselves, and the pod has existed for centuries, something never even hinted at by the former show. (The two shows are confirmed to take place in the same continuity due to Rikki's appearance in the latter.) The natural mermaids appear to have no idea that the girls from the first series existed, as Mimmi and Ondina are surprised to learn about Rikki. It's justified why the former show's girls didn't show up in the latter show before Rikki's appearance (they'd moved away; this had happened to Emma before the former show even finished), but not how the former show's girls (or Miss Chatham's squad in the former show's backstory) completely missed the Mako Pod every time they went swimming, except in the meta sense that Mako Mermaids and its backstory hadn't been planned yet when H₂O was being created.
• Heroes:
  • Season 2 has a clumsy example. In the middle of the first season, it's revealed that Matt's wife is pregnant. This causes a few fans to wonder if the baby is really his, since she cheated on him earlier in the season. However, in an episode set five years in the future, we learn that the kid is named after Matt, sends him crayon drawings of himself and mommy from hiding, and, most tellingly in a show where almost everyone with superpowers gets them from Super Powerful Genetics, has a power. Then in an early Season 2 episode, Matt says that whoops, turns out it wasn't his kid after all. In "Fight or Flight," a later Season 2 episode, however, it is implied that he has accepted that it isn't his child without any actual proof, when he has a nightmare in which his wife chastises him for not reading her mind and learning the truth, so this may be a reversion more than rewrite.
  • In S1, Mohinder was originally said to have been two years old when his sister died, but they changed it so that he was born months before she died in order to wrestle Molly into his plotline.
  • Season 3 retcons Sylar's murderous ways as a side effect of his original ability. His ability to know how things work apparently gave him a "hunger" to kill people just so he can satisfy his fix for more power. This of course ignores that S1 and S2 showed him utterly reveling in murder, even when he didn't have any abilities. The writers have a go at fixing this one again, with Sylar shown to have gone through a guilt ridden phase around the time the series began, presumably redecorating appropriately. The plot that tried to explain this retcon also retconned Elle's background, as she is portrayed as relatively normal and even caring and guilt-ridden, rather than sociopathic and murderous as in season 2. This contradicts season 2, in which she states she was diagnosed as a sociopath at eight.
  • Take it as a retcon or a further loss of his humanity, but as of season four Sylar can seemingly suppress his hunger (evidenced by a casual road trip that lasted for several episodes next to tasty brain Luke) but still revels in his murderous behavior, perhaps moreso.
  • It seems that every other episode that something new is added to Noah Bennet's back story that wasn't there before. A prime example in season 4 when Noah almost participated in an affair during the events of season 1, when his daughter was in danger. Then later in the season, he had a deceased wife that had never, ever been mentioned in the plot before.
  • Claire having magic blood in Series 2 which can resurrect anyone from the dead, such as when Noah Bennet was killed after being shot in the eye. This is promptly forgotten after this incident and by Series 4, when her biological father Nathan is killed, reviving him in this way is never an option.
  • The actual cause of what gives them powers has also been retconned several times. At first its hinted at being a genetic trait which has something to do with the brain. This made some semblance of sense, until an Eclipse somehow turned everyone's power off. And then Hiro's mother had some kind of mystical power that was the key to abilities.
  • There's also Sylar's parentage. When he's first seen, it appears his parents were ordinary people (indeed, they're too ordinary for him). It's later revealed that he's adopted, and that his real parents are Angela and Arthur Petrelli. This is later retconned too, and it's revealed that his real father was an evil psychopath that killed Sylar's mother.
• Highlander is full of retcons between the films and the series. One huge example is Connor's fight with The Kurgan. The series retconned it to simply being a really big quickening from a normal battle rather than The Prize. Other retcons were about the immortals' physiology and abilities. Series immortals died temporarily when injured, unlike the film, where they just kept on going and could walk under water without drowning.
• The MTV Reality Show The Hills was a major offender when it came to this. During the pre-credits voiceovers, new dialogue and/or footage would be added to address what the episode's focus would be, even if it conflicted with events as they were seen in previous episodes. These included, but were not limited to, pleasant conversations between characters being reframed to look more antagonistic, characters describing events that never could have occurred within the timeframe of the show, extra dialogue being looped into conversations (said when the camera isn't on them) to change the focus of the plot, and deleted footage that showed characters doing activities that they were never seen to have done in the previous episode. This fed a lot of fan speculation as to whether or not the show was scripted.
• At the end of season five of House, the main character loses his mind (said to be caused by a number of reasons, from too much Vicodin to Survivor's Guilt over Kutner and Amber's deaths) and is scared enough to go to a mental hospital. At the beginning of season 6, it's claimed that he just needs to be off the pills and "learn how to love", which the Girl of the Week Lydia teaches him how to do, because apparently Stacy didn't count. Weirdly, after a couple of mentions, Lydia is never mentioned again, and there's big sad analyzing with Kutner/Amber/Stacy hallucinations in the finale, maybe as an Author's Saving Throw.
• House of Anubis has two in the third season:
  • The main villain is Robert Frobisher-Smythe, who'd been mentioned several times during the other two seasons. In the first season, in fact, he was explicitly mentioned as being dead. This was confirmed by Nina seeing his ghost. Suddenly in season three, however, he was just in cryogenic sleep and could be re-awakened.
  • Season two introduced a new section of the house, underground tunnels, where the students had to due tasks to complete the current treasure hunt. But in season three, this tunnel suddenly gained a new hallway, one that the characters acted as though existed the entire time.
• Kamen Rider Double has an example in the form of Katsumi Daido/Kamen Rider Eternal, the Big Bad of The Movie. There, we were told that he was a kind-hearted boy who died of an unspecified illness, prompting his bereaved scientist mother to volunteer him for an experimental plan to revive the dead as Super Soldiers; unfortunately he Came Back Wrong, regarding himself as an "undead monster", and plotted to kill off the entire city of Fuuto so they would share his pain. Then after the series ended, Daido was given his own focus movie that retconned almost everything about him in order to make him more sympathetic. Besides changing the manner of his death (hit by a truck), it was shown that the revival process wasn't faulty at all: Daido had been a good person all along, but went off the deep end after failing to save an evil Mad Scientist's test subjects.
• M*A*S*H: Radar was flanderized over the course of the series, evolving from a gruff unmotivated draftee to a sweet, innocent kid. Perhaps the most egregious example comes from his smoking cigars: early on, he's often seen with his feet up on Lt.Col. Blake's desk, helping himself to the CO's cigars. A few seasons later, Col. Potter has to teach Radar how to smoke a cigar, as he apparently has never done it before.
• Monk:
  • The series has had a couple involving Trudy's death. First, it's originally stated that Monk was there by Trudy's side as she died from the car bomb, but later episodes show he was across town. Additionally, Monk originally did not know that the reason she'd left that fateful day was to pick up medication for his brother Ambrose, and Ambrose personally blamed himself for her death as he felt that if she hadn't done so than maybe she'd still be alive. However, in Ambrose's first appearance, along with a flashback to the day of her death in the series finale, it is mentioned that Trudy is picking up Ambrose's medication.
  • Additionally, in one episode as part of a gang of Chinese criminals' plan to lead him to Monk, they attempt to trick him with fortune cookies. One of the fortunes states that he will receive money from an uncle, which Randy rebukes since he only has two aunts and no uncles whatsoever (it was actually referring to tax return money, the uncle in question being "Uncle Sam.") Two seasons later, another episode is kick-started with the death of Randy's uncle. Not only that, but Randy visited his farm several times as a kid.
  • One episode says that Monk did not have his psychological quirks until after the death of his wife, however another shows he still had extreme OCD as a teenager.
• In My Parents Are Aliens an episode showing how the aliens met the children shows that Brian and Sophie originally had disguises resembling the presenters of Crimewatch before changing into their familiar forms. Later in the series 7 finale they said that they stole the identities from the children's real uncle and aunt, also named Brian and Sophie.
• In Night Court, Brent Spiner played a character named Bob Wheeler from West Virginia. After a number of people from that state complained it was later revealed he and his family had actually come from Yugoslavia.
• Once Upon a Time:
  • The series does this with the Frozen mythology - despite following the continuity of the movie almost directly. Anna and Elsa's mother (renamed from Idun to Gerda) is revealed to have two sisters Ingrid and Helga. Ingrid had ice powers like Elsa and accidentally killed Helga with them. As a result Gerda sealed Ingrid inside an urn and got the trolls to erase her sisters from the memory of everyone in Arendelle. This is also implied to be how the parents knew about the trolls (through Gerda) whereas the movie implies that the king was the one who knew.
  • Season 3 retcons Cora's backstory into having an illegitimate daughter before Regina who she gave up in order to marry into royalty.
  • The pilot episode has Snow White remark that Regina "poisoned an apple because she thought I was prettier than her". We later learn that Regina's vendetta has nothing to do with her being pretty.
  • The third episode has the prince ask if Snow ruined Regina's life and she replies that she did. The reason is revealed to be that Snow told Regina's mother about her daughter's romance with the stable boy - resulting in his death and Regina being forced to marry her father. In the episode that shows this, Regina lies to the younger Snow White and says the stable boy simply ran away - with the aforementioned episode implying Snow later found out the truth. However she finds out about the death right before she bites the apple - which chronologically takes place after the conversation between her and the prince.
  • Season 5 adds another retcon between Regina and Zelena. This time it's revealed that the two actually met when they were children, and were even friends for a short time. After the two sisters discovered they were related, their mother believed that Zelena would jeopardize her plans to make Regina queen, so she forced them apart again and wiped their memories of their meeting.
  • It's revealed right from the start that Regina got the Dark Curse from Rumplestiltskin, thereby implying that he's the one who created it. But then Season 4 reveals that he just stole it from the cave where it had been hidden, suggesting that he didn't have anything to do with its creation. This is confirmed in Season 6, with the revelation that it was actually the Black Fairy, Rumple's mother, who actually created the curse.
  • In a mid Season 2 episode, Cora tries to remove Emma's heart but is magically blocked, with the implication that it's merely because of Emma being the Savior. Near the end of Season 6, however, when the Black Fairy tries to do the same, it's revealed that Emma's heart actually contains powerful Magic Music which protects her.
• The first two seasons of Parks and Recreation involved a fairly prominent characted named Mark Brendanawicz. He begins a serious relationship with Ann but they break up and he's Put on a Bus at the end of season 2. In the following seasons the characters act as if Mark never existed.
  • Before his departure he gave Leslie plans to build a park on Lot 48. Leslie eventually succeeds in getting the park built, but Mark's plans were never used or mentioned.
  • The writers planned to have Mark reappear every once in awhile, but that idea was scrapped since Paul Schneider had no interest in returning to the series
• Power Rangers:
  • Mighty Morphin' Power Rangers has one when it came replacing Rangers. In season 2, when Jason, Trini, and Zack had to leave, the team needed to acquire a special sword to transfer their powers to Rocky, Aisha, and Adam, but in the following season, when Kimberly needed to give her powers to Kat, she just handed her power coin away. The comic Mighty Morphin Power Rangers: Pink also included this event in its past, but explained that since the Sword of Light hadn't been used then, Kim had actually retained her powers but was unable to morph anymore due to lacking a physical morpher. Also, the ages of the original Rangers were 16-17 as evidenced by the fact that they drive cars. The original finale "Doomsday" would see the rangers battle and defeat Rita and give up their powers and go to a prom. However, based on the popularity of the show, Saban altered the episode to not be a finale and leave room for more story. The prom part was cut out and the Rangers were retconned to being 14-15 in order to keep them around longer.
  • Power Rangers Ninja Storm originally indicated that it wasn't part of previous Power Rangers continuity, but their team-up with Power Rangers: Dino Thunder (and before that, the 500th episode "Legacy of Power") shoved it back in.
  • Power Rangers Operation Overdrive changed Power Rangers Mystic Force's own rules when, during the anniversary episode "Once A Ranger", it's stated that all powers are connected to the Morphing Grid, retconning Mystic Force's magic reasoning.
  • Power Rangers Samurai retconned the previous season, RPM, out of continuity with every other Power Rangers series, and this was originally intended to be done to every Disney era show until the production staff saw what was going on with Kaizoku Sentai Gokaiger and had to backpedal on going through with it. Suffice to say, fans did not take it well when Clash of the Red Rangers aired. The reason behind this is because Jonathan Tzachor publicly stated he hated the Disney era shows and wanted to disregard them. He also has tried to say that every Power Rangers season is out-of-canon with each other after In Space outside of the crossovers.
  • Power Rangers Megaforce essentially retconned the Sentai series from before Kyōryū Sentai Zyuranger as well as the suits from Gosei Sentai Dairanger as just powers that weren't brought to Earth.
• Prison Break did this with alarming frequency, to the point that they actually resurrected a character whose DECAPITATED HEAD WAS SHOWN ONSCREEN. This was retconned as a female guard helping her escape before the assassin had a chance to behead her. Instead, the assassin chose to behead the guard and deliberately left the package in a dark place, so nobody would look at the features.
• Red Dwarf is full of retcons. Major examples include the number of the ship's original crew being raised from 169 to 1169 (and raised to 11169 in the books), Lister having his appendix removed twice and Lister's relationship with Kochanski being altered from simply someone Lister was interested in but never asked out to ex girlfriend.
• Riverdale: The later seasons try to portray Alice as a Parents as People type as opposed to being an Abusive Parent. However, she never atones or acknowledges her behavior, instead doubling down.
• One of the cruelest endings in live-action sitcoms came from Roseanne, which saw Dan, Roseanne's husband and Conner family patriarch, reveal to have actually died in the previous season's finale from a heart attack and that the entire following season was a book Roseanne was writing. The 2018 revival tosses all of that into the Discontinuity Bin by showing that Dan's alive and well, though wearing CPAP machine gear for his health.
  • It's worse than that, though. The original series finale also implies an entire alternate universe in which many of the events of the show, long before the final season, must have been totally different in order to explain the different sexualities and relationships (Mark/Darlene? How did THAT happen?) but there's no time to explain that. Then the revival makes entirely different retcons, throwing out most of the final season, removing certain characters, changing Harris's age, etc. Then when the show transitions to The Conners, even more changes are made, officially declaring that Jerry and Andy and Fred never existed, that Darlene apparently never went to college, etc. The showrunners have described it as a "multiverse" from which they can assemble whatever version of the characters they want, but the end result is that no one knows what elements of the original show are canon anymore.
• Sabrina the Teenage Witch:
  • The series establishes that the curse that will turn Sabrina's mother into a ball of wax is only supposed to last two years - so it should lift when Sabrina turns eighteen. Yet in the sixth season (where Sabrina is 20-21) it's still in effect. And when they go to the Witches' Council to appeal, none of them mentions that the curse should have expired by now.
  • Season 3 shows that cousin Amanda has a little sister Allie. She's never mentioned nor referenced after this.
• Although Scrubs doesn't usually do a lot of continuity, there are still examples of this:
  • One of the later episodes has a throwaway joke where J.D.'s friends claim that he cannot see women wearing their wedding ring. If that is the case, how was he able to see Carla in the later half of the show (5-9), or T.C.W., for that matter...
  • Another J.D.-related retcon is that in later season of Scrubs, he says he doesn't like beer. In the earlier seasons of Scrubs, however, he's clearly shown drinking beer in some episodes. Turk eventually calls him on this when he claims he can't drink beer, and he admits that he's been making up excuses to drink appletinis (which is itself a retcon, since part of the gag about the appletinis was that he doesn't even realise other people find it unusual).
  • Elliott from season 2 onwards can't say dirty words as a result of her mother's influence as a child, making up her own euphemisms. Yet she had no problem saying "penis" and "vagina" in several season 1 episodes.
  • Done ambiguously in regards to Janitor's Multiple-Choice Past. After mentioning his father dying when he was a kid, J.D. points out he met Janitor's father. Janitor responds, "You met a man."
  • Later seasons made jokes about J.D. knowing nothing about sports, despite him having sports memorabilia in his bedroom in earlier episodes. Zach Braff stated that this character trait was added after he mentioned to the producer that he wasn't interested in sports, and he thought it would be funny to add that to J.D.'s character.
• Smallville:
  • The most egregious example of this was a vital clue hidden in a stained-glass window that hadn't been there in the previous episode, as well as the same window had been destroyed several times over the course of the series. The ridiculousness of retconning a window a week after it had last been seen casts a shadow on what would have been otherwise well-written.
  • The original meteor shower that brought Clark to Earth now includes Davis 'Doomsday' Bloom several feet away. Lionel's agents manage to reach Davis after the Kents have already carried Clark home.
  • The show introduced a major character from the comics, Jimmy Olsen, in S6. He had a supporting role for the next three years, then they decided to kill him off in the season finale. To keep the show in line with the comics, they had his funeral reveal that his name is actually Henry James Olsen, and it was implied that his previously unheard of little brother was the real Jimmy Olsen. Three years' worth of retcon!
• Spooks the main arc of Season 9 qualifies (it qualifies as other nasty tropes too) Lucas is actually Evil!Lucas… turns out he was " lying to himself" being the perfect spy: it all comes out of nowhere and makes NO SENSE whatsoever.
• Retcons galore in Stargate SG-1:
  • In the episode where Zat guns (a type of stun-gun) were introduced, they were shown to be capable of disintegrating people and things if they were shot three times. This was used once to get rid of dead bodies that the crew didn't want to have to leave on set, once to destroy a dead body so SG-1 wouldn't get noticed, and once to destroy evidence of SG-1's presence during a time-travel adventure, then dropped completely because it was silly and overpowered. Now zats only stun people, or kill them if shot enough times. This is referenced in episode 100 "Wormhole X-treme!". On set for the show-within-the-show, someone suggests giving their stun gun a feature to dissolve dead bodies so they won't have to be there for the romantic scene that follows, but the idea is denounced as stupid.
  • Another under-noticed retcon is the fact that Hathor was able to turn humans into Jaffa, which is mentioned both times she appears but never again. Apparently the other Goa'uld forgot how to do it too?
  • The show retcons a number of things from the original movie, despite the movie itself still being mostly canon:
    • Ra wasn't the last of his species. The series suggests that the Abydonians were tricked by Ra to think he was the only one, to ensure their loyalty.
    • The Goa'uld didn't look like Protoss with mouths. Within the series this is never explained, but in extended universe material it says that Ra's previous host was an Asgard, which does look somewhat like the alien shown in the movie. Apparently the Asgard can't make for healthy hosts.
    • Abydos isn't "on the other side of the known universe," but one of the closest planets to Earth, which is used to explain why other addresses didn't work until they readjusted the dialing software to account for stellar drift. Non-canon explanations state that the technicians during the first Abydos mission were incorrect with their calculations for distance.
    • A few names were changed: Jack O'Neil becomes Jack O'Neill (which is lampshaded by O'Neil's statement that there's another Colonel O'Neil with one L, and "he has no sense of humor"); his wife Sarah and son Tyler become his ex-wife Sara and his son Charlie; Daniel's wife Shau'ri becomes Sha're; and the fictional Creek Mountain complex becomes the real-life Cheyenne Mountain complex. Sha'uri became Sha're because Michael Shanks (the actor playing Daniel Jackson in the series) had trouble with the "au" diphthong.
    • One of the better retcons from the movie was the reason for Daniel Jackson's career nosedive. In the movie, he's laughed at for arguing, with evidence, that the pyramids are older than we know, simply because he didn't know who built them. The series changed this so that instead of one of his mocking audience suggesting aliens built them, it was Jackson himself which makes his getting laughed at perfectly understandable.
    • One of the more plot-significant retcons has to do with the fact that the symbols on each gate are now the same except for one (the symbol designating the gate's point of origin), so they don't have to spend half of every episode figuring out the return address like they did in the movie. All addresses are based on points in space derived from Earth constellations.
    • In order to fit the constraints of a TV series, they dropped the language issues that were such a big part of the plot of the movie, and now everyone in the galaxy seems to speak English. This is never addressed in-universe, however one of the writers flippantly suggested that the Stargate injects Translator Microbes into travellers. Which work for every language except Goa'uld, Asgard, Ancient, and Unas, apparently.
• Mid third season of Stargate Atlantis shows the first shot of the interstellar gate bridge. The first episode of season four shows its completion. Watch carefully in this scene. At one point, we see Carter moving past a computer with a wire frame of a Stargate, notably looking like it has an iris on it. Fastforward to episode seventeen where an entirely brand new line is added into the "previously on" segment, where McKay claims there is actually no need for the midway gates to have irises at all. This change is made for no reason other than to have an episode where the Wraith board the midway station and destroy it. The fallout of this episode is that the I.O.A refuses to build another because they're afraid of the same tactic. The possibility of building another and just adding irises is conveniently never brought up, so it would appear this retcon was all for the sake of justifying the permanent removal of a quick way back to Earth from the series.
• The Star Trek franchise is a Shared Universe spanning more than fifty years, with writing of, to put it kindly, variable quality. Naturally, it has had many retcons:
  • The Klingon makeup change was just better budgeting from the show to the movies. Worf's scene in Deep Space Nine in the flashback turned it into an actual plot point.
    • The reference was meant to be a quick joke about the effects budget in an episode that was already tongue in cheek. The writers expressed total bafflement over how much of an uproar it had created with the fandom. Reactions in Usenet newsgroups ranged from "can't you guys relax and take a joke", to "we demand answers NOW!" to "We were fine ignoring it until you morons brought it up". The same lunacy also made another Worf joke from that same episode, the "The Great Klingon Tribble Hunt", official canon. Canon is serious business.
    • In the end, Star Trek: Enterprise resolved the matter once and for all, proposing that the change was a side effect to the cure for a fast-spreading plague.
    • The changes we see in Kang, Koloth and Kor are alluded to as well, as the episode ends with a Klingon doctor speculating on the fortune to be made in the reconstructive surgery business — an option for seasoned veterans who had acquired fame and fortune in their younger days, but probably not for young starship commanders looking to make names for themselves. (And neatly ties up the early version of the Klingon makeup used in Star Trek: The Motion Picture as the result of botched reconstructive surgery.)
    • The Klingon language brought about a minor retcon. It was decided, while it was being developed, that it shouldn't contain a /k/ sound, because "K means Aliens" was already a well-established cliche that they wished to avoid. The problem being, of course, that the language was being written for a race with a K in their name. It was then made canon that they weren't really called "Klingons", that was just a minor mistranslation, and the actual name was "thlIngan".
    • Then along comes Star Trek: Discovery (taking place between ENT and TOS) and completely ignores this explanation with an even weirder look for Klingons (e.g. even more prominent ridges, no hair at all).
    • The season two Retconned that, as the Klingons now sport hair (the argument introduced being they shaved their heads when going to war). More noticeable than the hair, released photographs of Mary Chieffo as L'Rell show her head is not nearly as non-human as it had been in season one, and her skin tone changed from the purple/lavender it appeared in the first season to a more "traditional" look◊.
  • Exactly the same thing happened to the Ferengi between Star Trek: The Next Generation and Deep Space Nine, turning from a mighty empire with warships that seriously threatened the Enterprise into a one-note joke race of scheming cowards.
    • The above shift was justified in Star Trek: The Lost Era novel "The Buried Age", which established that Grand Nagus Zek had been building up the Ferengi's military reputation to create an intimidating impression out of concern that the Federation's moneyless economy was a sign that the entire society were all basically lunatics, unable to comprehend such a way of life.
  • TNG's pilot, "Encounter at Farpoint", implied that the Ferengi were known for eating sentient beings. This was never brought up again.
  • TNG introduced an entire new race mid-series: the Cardassians. They had never been mentioned before, and yet in their very first episode, it is made clear that the Federation and Cardassians had been at war. And recently enough to be living memory for several crew members. Indeed, the plot of the Cardassian introduction episode is all about the psychological fallout from them. They got a lot of mileage out of this retcon.
  • And then again during TNG, the Borg changed from assimilating only technology to being essentially techno-vampires. Later on, in VOY, Chakotay meets a group of former Borg drones, some of whom claim to have been assimilated at the Battle of Wolf 359. Except that particular cube was destroyed with all hands.
  • In the final episode of Star Trek: The Original Series, "Turnabout Intruder", Dr. Janice Lester pulls a Grand Theft Me on Kirk to break through the glass ceiling, because even in the utopian future of Star Trek, women were apparently barred from service as starship captains. This embarrassing piece of 1960s male chauvinism was retconned out by attributing it to the delusions of a mentally unstable woman, despite Kirk's explicit on-screen acceptance of both the accuracy of her accusations, and the injustice of the policy. Subsequently, Star Trek: Enterprise gave the NX-02 an all-female bridge crew.
  • The revelation made late in Star Trek: Deep Space Nine that Dr. Bashir is a genetically engineered superhuman explains how he was able to beat O’Brien in racquetball so many times and shows that he most likely mistook a preganglionic fiber for a postganglionic nerve on purpose to not draw suspicion to himself. But this also causes numerous conflicts with earlier episodes and reveals that he could win every game of darts against O'Brien. Not only does this make their entire friendship seem like a farce, since playing darts is the chief activity they're seen enjoying together, but it contradicts the episode "Visionary" where O'Brien's foreknowledge of where Bashir's darts are going to hit was used to show that he had really been to the future. Then the episode "Distant Voices" is centered around an alien probing his mind and drawing out his deepest secrets, but him knowing himself to be the product of illegal genetic engineering never comes up.
  • Also in Star Trek: Deep Space Nine, Sisko's status as one of the holiest people in all of Bajor, the Emissary of the Prophets and the one who found the Celestial Temple, was not realized until around the end of season three, even though he takes on that role from the first episode. He's so holy that every Bajoran walks on eggshells around him and is deeply honored to even be in the same room as him. Even Kira later admits she doesn't dare to get to know him better because he's the Emissary. And yet, initially, people don't treat him any differently than any other Starfleet officer. Kira even angrily complains to his superiors behind his back. In a custody case he was deemed an appropriate judge by a Bajoran because he "is also a father", not because his holiness is second only to the Kai.
  • Taking this further, if one revisits the Season 2 TNG episode "Unnatural Selection", where the Darwin station scientists are engineering perfect humans, those scientists are doing something wholly criminal (by any measure several orders of magnitude worse than what Julian's parents did) and really should have been taken into custody by Picard. This is somewhat mitigated by the The Lost Era Novel (The Buried Age) which revealed Darwin station was to be used as a test case to explore the field despite fear that it would spiral out of control.
  • Star Trek: The Next Generation has a revelation that excessive warp speeds are causing holes in spacetime (in an Anvilicious Aesop about pollution and the environment), which prompts the Federation to limit ships to Warp 5. Characters in a couple of subsequent episodes pay lip service to the "speed limit" right before they break it, but after that it is forgotten completely, with the general Fan Wank being that an improved version of the Warp Drive that didn't mess up subspace was invented. May also apply to what ought to be the inevitable ramifications of a new technology or application thereof, such as retrieving a heretofore-disintegrated crew member out of the pattern buffers of the transporter. In Peter David's Star Trek: New Frontier novels, there's an offhand reference from a character who can "see" spacetime about the damage still being done by warp travel. This got so noted that fanfiction writers No-Prized it, coming up with the dual ideas of the ruts worn in spactime healing over a period of time and simply changing your routes to avoid cumulative Spatial Fatigue.
  • In Star Trek: Voyager, The Mole Seska claimed to Chakotay that she impregnated herself by stealing his DNA. She also told Kazon leader Cullah, who she was sleeping with, that the baby was his. After the baby was born and was clearly a Cardassian/human hybrid with no Kazon-like features, Cullah was naturally pretty pissed off, which led us into the season ending cliffhanger. However, between seasons everyone decided that the Kazon weren't up to the job of being the show's big recurring bad guys they were envisioned as, much like the Ferengi on TNG, so they decided to drop them from the show entirely. This involved Seska dying, and Cullah running away with the baby. Naturally, fans wouldn't accept Chakotay's kid being raised by the Kazon, however unwillingly he fathered it, so just before this the Doctor reveals it is actually Cullah's baby after all. The baby's appearance is Hand Waved by saying there's never been a Cardassian/Kazon hybrid before so before now no one knew what one would look like, and it'll probably develop Kazon features as it ages.
  • An in-universe case (or series of cases, really) of this forms the basis of the two-part Star Trek: Voyager episode "Year of Hell". The Big Bad has developed a weapon that lets him use retcons to change the timeline (while he himself is protected by Applied Phlebotinum). He first uses it to reverse a stunning defeat to his species... Only to discover that he's now made them vulnerable to a whole new problem. A subsequent modification also erases his wife from history. He spends over a century trying to put things right, never satisfied no matter how close he gets. (Also provides a handy Reset Button: evidently, destroying his ship undoes all his Retcons, and Ramming Always Works).
  • And then there's the question of currency, specifically whether the Federation uses any during the 23rd century. There is at least one mention of a crewmember "earning their pay" in a TOS episode, though that might have only been a colloquialism Kirk was using. In "The Trouble with Tribbles", we see what clearly looks like trade with a human salesman - it's hard to imagine that guy was just in the business of giving away these critters for free. Then by The Voyage Home Kirk has a quote about people in the 20th century "still using money", implying that they don't anymore. You might think that they stopped using money at some point between TOS and the fourth movie, but the tone and reactions in the scene seem to indicate the Enterprise crew is completely unfamiliar with the concept of currency - so the change wouldn't have occurred in their lifetime. And then, a later movie has McCoy snark that he'd give "real money" to have the movie's villain stop talking, possibly indicating that McCoy - generally shown to be an older, more curmudgeonly figure than Kirk - witnessed the changeover while Kirk had missed it. And of course, by the TNG era, they beat us over the head with the fact that the Federation doesn't use money anymore (except for outside trades with other species, especially the Ferengi). Enterprise seems to hint that currency was abandoned when the Federation was first formed, a few years after the end of that series, but it's very vague about it. And then, to add further confusion, the 2009 movie has a scene that takes place in a bar, on Earth, that clearly seems to operate on capitalistic principles (plus the Nokia phone in Kirk's uncle's car). Now, that movie takes place in an alternate timeline, but since the two timelines diverged on the day of Kirk's birth, it would mean that even in the original one, currency was still legal tender at least until that day. To sum it up, it seems like we're now just meant to vaguely accept that they've phased money out by the 24th century without asking too many questions about how they did it or the precise moment when they did.
  • Trills make their first appearance in an episode of Star Trek: The Next Generation ("The Host"). Here, the symbiont clearly has total control over the host body and considers transporters to be harmful. In Star Trek: Deep Space Nine, the makeup is completely different (mainly because they didn't want to ruin Terry Farrell's looks with a rubber forehead), the host and symbiont create a combined personality, and use of transporters does not appear to be an issue. Additionally, Trills are virtually unheard of in their introductory episode, making The Reveal of Odan's true nature a surprise, while in DS9 they're indicated to have been a known quality for ages, with Sisko having been mentored by Curzon Dax, and Jadzia Dax remembering a sexual encounter with Dr McCoy.
  • In "Space Seed", the Eugenics Wars (set during the 1990s) was mentioned by Spock to be in the "era of your last so called World War". In the Next Generation era, World War III is said to happen at least five decades later. Additionally, author Greg Cox, who wrote several Trek novels set during the Eugenics Wars era, observed that the passage of the real 1990s necessitated reimagining the Eugenics Wars as a less overt conflict that happened around real life events and may not have been known to the general public. The episode where the Voyager crew visited The '90s did not depict an Earth embroiled in a world wide conflict with genetic supermen. Cox also humorously noted (in one of the DVD extras in Wrath of Khan) that Khan didn't exactly appear on the cover of Time Magazine.
  • The use of phasers. In the original TOS pilot "The Cage", the Enterprise crew is using lasers. All subsequent episodes use phasers, and a TNG episode scoffs at the idea of lasers being a threat to the Enterprise-D. In another episode, Worf tells a time traveler that the 22nd century didn't have phasers. Then along comes ENT, set in the 22nd century, and suddenly we have phase-pistols, phase-rifles, and phase-cannons. Despite the slightly-different names, they're exactly the same as 24th century phasers, just weaker and with fewer settings.
• St. Elsewhere:
  • In "Breathless", Dr. Auschlander mentions that St. Eligius was founded in 1932. He then asks Dr. Westphall if he ever met the hospital's founder Father Joseph McCabe. Westphall says that he never did. The two-part story "Time Heals" establishes that the hospital was founded in 1935 and that Father McCabe had not only known Westphall as a child but was a mentor to him during his troubled teens.
  • In "Give the Boy a Hand", the artist Alex Corey tells Dr. Auschlander that Father McCabe died while his father was painting his portrait years earlier. In "Where There's Hope, There's Crosby", it is revealed that the 90-year-old McCabe is still alive but he is paralyzed as a result of ALS when he returns to St. Eligius after spending the last 30 years among the Hopi tribe in Arizona.
• Supernatural:
  • The first couple shapeshifters they meet have to strip off their current skin to reveal their new form. The first they meet takes a long time to transform in what appears to be a painful process, the second takes almost no time to stripe their skin off, and the others don't even strip their skins off, they just transform.
  • Trickster secretly being the Archangel Gabriel. At the time of his creation in the second season, angels weren't even planned to appear in the show -That decision was made during the third season, due to the Writer's Strike cutting the season short. Then in the fifth season they're revealed to have been the same being all along.
  • The cure for vampirism. In the earlier seasons it was explicitly stated that there was no cure, but season 6 introduced one anyway. They try to Handwave it by stating the Campbells were keeping it secret, but this is flimsy at best -Wouldn't the logical thing to do be to spread knowledge of the cure to as many hunters as possible, so that more victims of vampires could be saved?
  • The cure for lycanthropy. In season 2, an entire episode was dedicated to the boys trying to find and stop a werewolf and eventually having to kill a girl Sam had feelings for because they could not find a cure for her. In season 12, Claire, a friend of the Winchesters is bitten and they are able to save her with a little known cure from the Men of Letters using some unknown chemical and the blood of the siring werewolf. Claire is saved. It's handwaved as she was saveable because she hadn't fully transformed and there hadn't been a full moon yet.
  • In season 8, we learn that hunters were intended to have a scholarly counterpart, the Men of Letters, that handled the research, but that the American chapters had been so thoroughly wiped out, no living hunter had ever heard of them. Dean and Sam, hunters, actually should have been Men of Letters, but their grandfather was was sucked into the future where he was killed before he could tell John about his legacy. This retcon was further expanded when the British chapter arrived in America to fix what the American hunters have broken... six years after the Apocalypse. They knew the American hunters were grossly outnumbered and relied on a very loose network of trial-and-error information that would be hugely helped by the arrival of a highly organized society steeped in lore and knowledge, but they chose not to intervene from the 1960s all the way to 2016. Their excuse? They didn't want to meddle in American affairs.
• Super Sentai Does this to its own canon on occasion, both within series and externally.
  • Originally, Himitsu Sentai Gorenger and J.A.K.Q. Dengekitai were not part of the Super Sentai canon that was established with Battle Fever J and made notable when Kousoku Sentai Turboranger was stated as the eleventh team in theri beginning-of-series crossover event and that there were ten before them with Battle Fever J being the first. However, when Chouriki Sentai Oh Ranger was labeled at the 19th and not the 17th when the series was introduced, it meant that Goranger and J.A.K.Q. were put back in retroactively. In Explaination, Toei has explained they were not Legally able to count Goranger and JAKQ as part of the greater Sentai canon due to the nature of who was responsible for and involved in production; Goranger and JAKQ under Shotaro Ishinomori and his company; whereas Battle Fever J, Denjiman and Sun Vulcan following it had limited partnership and invovlement with Marvel Comics. But they were able to clear up such licensing issues in the 90's due to Shotaro Ishinomori's Terminal cancer having him Give Toei the rights to all of the things he produced with them, thus were able to finally back-include them.
  • Each Sentai series are considered standalone series; not out of canon with each-other, but not being reliant on other's continuity for major events they may conflict with. Which when they started doing the 'vs' crossover movies rubbed people the wrong way, as several of them are impossible due to each show's own canon. While Kaizoku Sentai Gokaiger was clarified that all Sentai series existed in the same world, it merely reinforced statements made in every multi-team crossover to begin with which went back to Turboranger at the beginning of the 90's. Meaning all the reasons why the various crossover films couldn't work because of conflicting canon were simply continuity errors to begin with. And since EVERY movie Toei makes has continuity errors with regards to the relevant TV series it's a movie of. This also clarifies and retroactively makes the World of Shinkenger in Kamen Rider Decade the World of Super Sentai.
  • Choujin Sentai Jetman starts off by announcing it occurs in the year 199X. Cut to two episodes later, and you see calendars announcing it's the year 1991.
  • Chouriki Sentai Oh Ranger starts off the first episode as announcing the year it occurs in is 1999. Cut to the middle of the series, and it's shown to be occurring in 1995, more to fit it in better with how Sentai series tend to be successive canon to each other; and Toei treats the series in all later media as occurring in 1995 (and at its end early 1996). Apparently no-one told Shout Factory, as it's part of their descriptive blurb about the show on their DVD box set.
• That '70s Show does this with a very early character, Donna's younger sister Tina. She appears in just one scene of one episode (Season 1 Episode 5) and is never heard from again. She is mentioned just once afterward in Season 2 Episode 6, in a joking Lampshadeing at the end by a soap- (or, more specifically, Soap-) style announcer: "And whatever happened to Midge's daughter Tina? [...] Confused? You won't be, after the next episode of That '70s Show!"
• The Office (US) has one with Andy Bernard. In one episode he introduces his parents as "Andrew and Ellen Bernard" after proposing to Angela. In subsequent episodes their names are Walter and Ellen Bernard, with Andy having a younger brother named Walter Jr. Andy also states that he was originally named Walter Jr, but his parents later gave that name to his brother who they thought to be more deserving of it, and renamed him Andrew."
• The West Wing In s3e5 "On The Day Before", President Bartlett vetoes the repeal of the 'death tax'. This is made up to be a huge deal, as it is an election year, and you don't support a tax in an election year, but it is considered 'shooting the moon', as the veto is supposed to be something that Bartlett has never done before. However, in s2e4 "In This White House", during Ainsely and Sam's debate on Capital Beat, it is mentioned by Mark Godfreed that Bartlett vetoed the Republican education package.
• Wizards of Waverly Place had the episode "Alex's Logo", where Mr. Laritate has mysteriously forgotten that Ms. Majorheely "texted in her resignation". This is due to actor David Henrie writing the episode, but that doesn't justify the error. The majority of fans have already shunned this episode from canon anyway, not without reason.
• The Worst Witch:
  • Season 2 retcons there being a Miss Gimlett who taught at the school - but abruptly leaves at the start of term. This teacher had never been seen, nor referenced in Season 1.
  • Charlie Blossom's second episode implies that he's related to Frank the caretaker through his sister. Season 3 adds his father Ted - and Frank's brother - as a character. But since Charlie's last name was Blossom already, the first one appears to be the goof.
• The Wubbulous World of Dr. Seuss: The second season retcons Yertle the Turtle's goal to be king of everything and turns him into an ordinary turtle.

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