Sarda: It's a simple "Re-Write Reality According To Your Whim" spell.
If a Retcon is changing the past, and a Cosmic Retcon is an in-universe changing of the past, then Retconjuration
never happened is the ability to create a Cosmic Retcon. Possibly a subtrope of Reality Warper, and was once mayor of New York may or may not involve leaning on or breaking the Fourth Wall, or pressing a literal Reset Button. (Although, depending on the scale of the Retconjuration instance, it may categorically force other in-universe examples of Reality Warper into becoming an in-universe subtrope of Retconjuration itself.)
There are two flavors of this trope, items that allow individuals to change the past (a Time Machine being the Trope Codifier) and individuals who can change the past under their own power. Said individuals may believe themselves to be deities, and depending on the scope of the power, they might not be wrong.
- Madoka uses her wish to do this in the final episode of Puella Magi Madoka Magica, completely rewriting the Magical Girl system so that no magical girl will become a witch, on this or any world, in this or any time past, present or future — which has the effect of completely destroying and remaking the universe anew. This doesn't come without a cost, however: Madoka essentially erases herself from existence after annihilating Walpurgis Night, since the power she expended during the battle would have otherwise made her a witch.
- Doing this is Tsukishima's entire schtick in Bleach. With each cut of his blade, he inserts himself into the target's past, up to the point where they think he's always been in their lives. Are you fighting him? Then he just has to cut you once and he instantly knows all your moves and how to counter them. After all, he taught them to you. Don't you remember? Oh, and if you think you'll be okay if you just avoid getting cut, that won't work either. He can just cut the ground and give himself infinite preptime to set up as many booby traps in the area as he wants, which somehow works even if it would've been physically impossible for him to set those traps (he uses exactly this tactic within a pocket dimension that had just been created the instant the fight began). Creepy.
- Black Butler: Angels have a variant of this. While they can't change the past on a world-wide scale, they can alter a single person's timeline to erase negative emotions associated with certain events. Since this action is against nature, however, the results are NOT pretty.
- In Another, a class is plagued by a curse kills members of the class and immediate family. This is caused by the presence of an extra, Dead All Along, student. Retconjuration comes into play because it's impossible to identify the "Extra" due to all the students having False Memories of that presence. On top of that, even official paperwork has incorrect information. Identifying the "Extra" can only be done after the school year ends, because everything reverts back to normal at that point.
- Transformers Cybertron: In Japan, it wasn't connected to Transformers Armada and Transformers Energon. In America it was, and any inconsistencies were explained in a comic book as being the black hole that was the main problem in TFC spreading its effects across reality, causing events to not always match up. This makes it the possible reason for every plot hole in any Transformers work.
- Spider-Man, Mephisto, One More Day.
- In The Sandman dreamers have the power to do this if enough dream the same thing at once; in the short story A Dream of a Thousand Cats, Morpheus reveals that at one point the world was ruled by cats with humans as their prey, but then a thousand-or-so humans simultaneously dreamed of a world of human dominance, and changed the world so that humans had always been dominant, and the world of cats never existed. A cat prophet is attempting to spread the word of this so that cats can dream the world back into its original state, but is implied to be doomed to fail, since even the cats themselves think it would be impossible to get a thousand cats to agree to do anything at the same time.
- Towards the end of the series, Delirium threatens Mazikeem to make her a half-faced demon waitress with a crush on her boss in the way she had been since the start and retcon reality so she had always been that way, and drive her insane wondering if Delirium had actually done it.
- Dr. Eggman in Archie Comics' Sonic the Hedgehog has a device called the Genesis Wave, allowing him to rewrite reality to a limited degree when powered by a Chaos Emerald. He not only used it on Mobius twice, he also used on the Mega Man world during its crossover.
- Ultimate Loki's power in Ultimate Marvel. He can shuffle space and time, insert or erase new identities into history and alter perceptions. He's restricted by being detected by Odin if he uses too much power, so he settles for Gaslighting Thor to make him and everyone around think he's crazy.
- Main universe Loki's newer incarnation has their magic defined as mucking with the narrative — yes, this means exactly what it sounds like. They could theoretically do anything, in practice however they're limited by the Theory of Narrative Causality and various butterfly effects. Example: So you've retconjured a girl into your uncle's past to create a weakness and defeat him in the present? (Fear Itself) That created a woman with very little choice or characterization who'll be rightfully pissed with you. (Everything Burns)
- Kobik, the Cosmic Cube girl, did this to Steve Rogers. His "new" past has him being a loyal Deep Cover Agent of Hydra, when he was originally nothing of the sort. Kobik did this on behalf of a former wielder of the Cosmic Cube whom she has latched on to as a friend and father figure namely, the Red Skull.
- In Pokédex, Stantler are revealed to have potential Reality Warper powers that do a Cosmic Retcon to the world of anyone who sees one, though it is unknown if they are really doing this trope or just altering memories. And Arceus is also capable of this - It turns out that he has been retconning in new regions constantly.
- Nero does this by accidentally creating an alternate timeline in Star Trek (2009), attacking the Kelvin and setting Starfleet down on a rather more militaristic bent. Also Vulcan is gone.
- In the Nicholas Cage film Next, the lead character has a limited version of this ability, which he uses to stop terrorists and score dates with younger women.
- The Wheel of Time's Balefire is a handy, portable way to do this, essentially burning the affected individual's "thread" out of existence. Not everybody's happy about this happening.
- Also, there's a Ter'angreal that does it. Uncontrollably. Only the most depraved villains are willing to even go near the thing.
- Ursula K. Le Guin's The Lathe of Heaven: George Orr's "effective dreams" change not only the present but the past as well: people don't realize that the world has changed (and was different in the past).
- Discworld yeti can leave a "bookmark" at some moment in time and later snap back to it if they are killed or in other troubles — now knowing what's going to happen and able to avoid it. They died out. Several times.
- Or, for those who aren't aware of the entirety of time, they most definitely did not go extinct. Ever, and if you thought they did then you're remembering wrong. Again.
- In the Jonathan Lethem novel Amnesia Moon this power is possessed by a number of people, which to some extent includes main character Chaos/Everett Moon. The effect is that as you move across the country, you can be thrown from one reality into another that's completely different.
- In the Young Wizards series there's a spell which overwrites the past of a wizard's universe with a copy of the past from an Alternate Universe. Combined with the portion of the spell which searches for just the right Alternate Universe to copy from, it's a powerful tool for maintaining The Masquerade.
- In The Emperor's Soul, Forging allows a practitioner to change objects by crafting and placing a magical stamp that tells reality that something in the object's history went completely different - for example, a Forger can restore a ruined table by "telling" it that it was carefully maintained, instead. Forging a person's history is also possible, but it requires such intimate, thorough knowledge about that person that only the very best Forgers can even do it to themselves, much less anyone else, and it only lasts a little while.
- The Mirage has this as a major driving force behind the plot. The novel takes place in a Mirror Universe where the Middle East is a unified democratic entity and the west is a mess of backward christian kingdoms and theocracies. On November 9, 2001, Christian fundamentalists attack the Tigris and Euphrates world trade center towers in Baghdad, sparking a war on terror and the invasion of the Christian States of America. Many years later, when a failed suicide bomber is taken in for questioning, he states that the world is a mirage; that history was changed somehow. An investigation of his apartment turns up a newspaper from September 12, 2001. From our world. It's later revealed this entire Alternate History was the product of a wish made by Saddam Hussein after he captured a Djinn.
- The Year of Hell two-parter in Star Trek: Voyager has the Krenim timeship, with a Ret Gone cannon the ship itself is insulated from ( unless the effect is triggered inside the ship due to damage sustained). The effects are limited to removing things from the timeline, but it can be modified to some things hit by while removing others (this is used for such things like removing a specific species while leaving their planet behind and inhabitable). The captain had spent 200 years desperately trying to undo the damage he inadvertently caused when he first used the ship... by doing pretty much the same thing, but with more careful calculations. In the end it does indeed end up affecting itself, undoing all the damage it caused by the simple expedient of having the creator never finish the design.
- In the Evillious Chronicles, this trope, referred to as a "Re_Birthday" is a power that beings called "Irregulars" (entities who aren't bound by the world's rules), with the way it works being described as being through taking the world and all the souls in it and reformatting it. As a rule, Irregulars always come in pairs, one to destroy the world and another to recreate it. An Irregular on his or her own can only destroy.
- The Chronomancer 2E Dungeons & Dragons supplement included three progressively stronger versions of this, in the Minor Paradox, Paradox, and Major Paradox chronomancy spells.
- Forgotten Realms has a spell that is a very limited version of this — Spellstrike. It completely negates all effects of one recent (in the same or previous round) casting of a spell or use of a spell-like ability, as if it just failed.
- The Sidereal Exalted boast a technique called Avoidance Kata which, when used early in a battle that turns out to have been a bad idea, allows them to have never got involved. Wounds already inflicted stay, but get a new cause- if you used it after the First and Forgotten Lion never has ripped off your arm, for example, you now will have got it caught in a grinding mill or something.
- They also have a martial arts style that essentially consists of punching your opponent's destiny. Fail to dodge, and you may suddenly be a married carpenter in Nexus.
- Similar to the above, Mage the Awakening has a Time spell called Shifting Sands, which sends the caster back in time by three seconds, allowing them to essentially redo the previous turn. Injuries do carry over, though. There is also a higher-level spell that allows one to place a temporal marker and Snap Back to it that has no time limit, but people tend to ignore or houserule it away.
- And that's not even the start of the time-related fuckery in the line. A Master-level Time spell allows you to temporarily rewrite your personal history so that, say, you studied martial arts instead of computer programming, allowing you to trade dots in Computer for dots in Brawl. The Cult of the Red Word, a Cannibal Cult that worships a demon made of living anti-history, has the ability to eat people out of existence if they're slaughtered in their sacred temple. And then there's the stuff Archmastery can do... by mistake.
- The Mistborn Adventure Game allows you to expend Spirit to edit previously introduced facts. It's very likely to fail, though, and really big Retcons are flat-out impossible.
- In Ratchet & Clank Future: A Crack in Time, Dr. Nefarious plans to use the Great Clock to create a universe where evil always wins.
- Touhou: a weaker version of this is the domain of Keine Kamishirasawa; she's able to "eat" the history of things, which changes the way people perceive the thing whose history was eaten. For instance, during the 8th game, she devoured the history of the human village so that they wouldn't be affected by the dangers of The Night That Never Ends (she restored it later); this way, the village was invisible to practically everyone, because people would be seeing a reality where humans never settled there in the first place (particularly powerful beings don't seem to be affected by it, though; Yukari, for instance, wasn't affected at all by Keine's ability and could see the village and its inhabitants with no problems).
- In AdventureQuest, The'Galin is a god that counterbalances creation—that is, uncreation. Uncreation induces a Cosmic Retcon over The'Galin's domain and only preserves Ripple Effect-Proof Memory to a few select individuals. One of the main plotlines of the game involves NPCs finding a way to persuade The'Galin to not uncreate the world of Lore, while his Starscream seeks to force it to happen.
- In BlazBlue, Phenomenon Intervention is an ability to replace an event with another possibility of the event. While some really powerful characters in the game have it, only 2 beings are capable of doing it to the whole world and retconning whole timelines: Takamagahara and Master Unit Amaterasu. The fourth game also reveals that Nine, one of the villains, has built a massive device called Requiem which lets her do this, though it's still imperfect.
- In the Shinza Bansho Series, there exists an outer-dimensional device known simply as the Throne. Should anyone ever fulfill the requirements to reach it and dethrone its current holder, then a person will be able to rewrite both reality and history with their own Law based on their desires. No one will notice the change to reality as, from their perspective, that's the way the world has always been. The only exception to this was when Marie took the Throne but left her predecessor alive, resulting the world continuing as is, just with her new Law in effect.
- The Trope Namer is Erf World, in which Retconjuration was actually Retconjured into existence as a subset of Naughtymancy after the authors didn't like a special they had given a minor character. However, nobody but the Titans can actually use it.
- 8-Bit Theater's Sarda uses Retconjuration with abandon and White Mage mucks up his attempt to retconjure the world to how he wants it, but he's more of a straight Reality Warper. Black Mage tries the same spell and it backfires (Sarda wrote the spell to rewrite reality to Sarda's will, not the caster's).
gets a minor one when he changes the archives so his red outfit was always blackhas never, ever tampered with the fabric of the universe.
- Clockstopper in Super Stupor (a side-comic of Something*Positive); he calls it Nut-Punching Father Time.
- It's also his favorite solution to everything.
- In the sixth act of Homestuck, a house-shaped treasure is introduced that gives the power to move through and alter canon. The power is explicitly different from time travel, which happens a lot, in that it is not bound by the requirement to create Stable Time Loops and can move through other universes and even into fictional contexts like Con Air, so long as they appear at some point in the Homestuck canon. Hell, even imagine spots can be retconjured by this power, as evidenced by the oil on Howie Mandel's sleeve on this page that only appeared after the house treasure was used.
- Germaine uses a "reset button" invented by Foamy in the web series: Neurotically Yours to initiate a series reboot.
- In SCP Foundation, SCP-140 is a book that chronicles the history of the Daevite civilization, an extremely unpleasant civilization (with human sacrifice, cannibalism, functional dark magic, etc.) that was wiped out at some point in the past. Whenever something that could be used to write with comes near the book (blood works best), more is written about the civilization and what was previously written changes, so that a battle that previously ended as a defeat becomes a victory - and suddenly archaeologists start finding evidence of them in the places and times it writes about. When first recovered, the Daevites were squished by Qin Kai in the 3rd century BCE. Now? They were squished by Genghis Khan, about 1400 years later. The reason it's classified Keter is because enough ink could bring the Daevites into the present day, and it's a fair bet current human civilization wouldn't be a match for them. Oh, and just in case you feel safe, they don't have every copy.
- The Foundation also has closely-guarded possession of several Thaumiel-class objects, almost universally capable of preventing or reverting back from even the worst K-Class scenarios. Several of them do so through Retconjuration.
- Ben Tennyson of the Ben 10 franchise, at least in the original continuity, can gain this ability by transforming into Alien X. Due to the transformation being Awesome, but Impracticalnote , Ben adamantly refuses to use it at all. The only time he willingly uses it after the initial incident is when the universe was completely destroyed early on in Ben 10: Omniverse and he had to use Alien X to rebuild it.
- Since quantum theory and magic are hard to tell anyway, look up Einstein-Rosen-Podolsky and Delayed Choice Experiment which come quite close to retconning history.