History Main / DelayedRippleEffect

* ''Film/ASoundOfThunder'': Giant translucent waves, which they called ''timewaves'', came out of nowhere and knocked people around ''[[Film/TheMatrix Matrix]]''-style, altering groups of species with every passing, over and over. Apparently, stepping on a butterfly in the past causes [[ForWantOfANail drastic changes in evolution]]. Fair enough. However, with the use of this trope, apparently simplistic animals species are more prone to having their evolutionary histories altered, and with each wave the environment gets more and more altered. Which means the metropolis got claimed by a fierce jungle, despite the fact that the residents are all still there, and the parks are filled with baboon monsters that are completely bulletproof, unless shot in the throat, and after X number of waves grow wings. The protagonists must hurry to a working time machine to save the butterfly, as they themselves will be altered by the final wave.

* A time-travelling akuma heads through a portal to the past in ''Fanfic/BabyBoom'', causing [[spoiler:Louis and Keva to disappear]], but as long as his portal is open, people's memories are unchanged, allowing the Rabbit holder to follow him and try to undo his changes.

* In the transformers: more than meets the eye, Brainstorm's briefcase is [[spoiler: a time machine that works this way to prevent paradoxes]].

-->-- ''Film/BackToTheFuture'', deleted scene

** In [[Film/BackToTheFuture the first movie]], Marty arrives in 1955 and almost immediately interferes with his parents' first meeting, meaning he will be [[RetGone erased from existence]]. Except it doesn't happen immediately; he's still got a week to convince them to get back together. The weird thing is that he's got [[RippleEffectIndicator a photo of himself and his siblings from 1985]], and his ''siblings'' start to fade out before he does, suggesting he's got more protection from his time travel shenanigans than others thirty years later. Then, once Marty succeeds, he and his siblings return to the photo instantaneously. (The filmmakers [[ShrugOfGod admitted that this makes very little sense]], but they don't have the benefit of our massive WildMassGuessing exercises.)

* In ''Film/HotTubTimeMachine'', obviously as an homage to ''Film/BackToTheFuture'', Jacob starts to flicker and disappear as his parents' mating session is interrupted.

* Discussed in ''Webcomic/ElGoonishShive'': Grace expresses confusion about how in ''Film/BackToTheFuture'' Marty is affected by the Delayed Ripple Effect and while at the same time possessing RippleEffectProofMemory. Justin tells her that the sequels don't make sense of this inconsistency and further that time travel is [[TimeyWimeyBall not allowed to make sense]].

* In the ''WesternAnimation/JusticeLeague'' episode "Hereafter", Vandal Savage, upon sending Superman back in time to foil an evil scheme of his, has to wait a few minutes to see the changes but gets to see the altered timeline has saved humanity in his present as he fades out and they fade in (briefly overlapping before he disappears)

* The ''Series/{{Victorious}}'' fic "[[https://www.fanfiction.net/s/11822231/1/Second-Chance-Second-Choice Second Chance, Second Choice]]" features a future version of Tori travelling into the past through MentalTimeTravel. As she starts to change her future by breaking off her first date with Jade before it can happen, the future versions of Jade and Robbie start to remember things differently, but it takes a few days before the consequences of Tori's actions outright ''change'' the future to the extent that future Tori remembers a timeline where Jade became a porn star and killed herself in her twenties.

* ''Film/BackToTheFuture'':
** Marty has a week to get his parents together before he will be erased from existence. Over the course of that week, a [[RippleEffectIndicator photograph he carries shows him and his siblings slowly fading away]]. On the DVD, the filmmakers admitted that this makes very little sense. To complicate matters even further, when he (mostly) restores the timeline, the photo changes back instantly.
** The interior of the Delorean seems to have a sort of time capsule effect. Nothing left in it is changed from the surrounding time ripples.
** Marty notably has a slightly different personality in the sequels, which nobody notices or comments on. His previously RippleEffectProofMemory also seems to adjust to his new family situation being "normal" almost immediately.
* ''Film/BackToTheFuturePartII'': Old Biff brought the sports almanac back to his younger self, setting him up to make a fortune, before returning the Delorean to his 2015 present. As he is getting out, he is starting to fade since his past self (in the new time-line) ceased to exist. Old Biff doesn't fade out entirely until Marty and Doc Brown time-jump since it is conceivable that had they found the top of Biff's cane before leaving 2015, they could have prevented the alternate 1985, but once they left, there was no more chance of changing the past back.

* ''Anime/TenchiMuyo'': This is the main plot of the first movie. Tenchi's mother is somehow killed in the past, and to keep Tenchi from vanishing in a week (when [[MadScientist Washuu's]] technology can't protect him any more), he and the gang travel back to figure out what happened and prevent it.

* ''WesternAnimation/XMen''
** In the animated series, there is one instance of changes in history causing NegativeSpaceWedgie-looking whirlwinds -- in the words of Apocalypse, a temporal storm -- that changed things as they went. Cable had to avoid them long enough to make his trip back to the present to figure out what happened.

* ''WesternAnimation/MeetTheRobinsons'': The changes made by the bowler-hatted man visibly ripple across the future, ditto for when Lewis reversed those changes. In fact, a scene is devoted to Louis giving the Bowler Hat Guy a tour of the restored timeline, repairing itself at an extraordinarily slow rate. On the other hand, Lewis's decision to never make Doris should have reversed things then and there, but it didn't happen until he faced Doris and told it so. Doris vanishes instantly.

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* In the final episode of ''WesternAnimation/SamuraiJack'', [[spoiler:after the death of Aku, Ashi manages to last until her wedding before RetGone kicks in and she's erased from the timeline.]]

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* In the 1983 novel ''Literature/Millennium1983'' by Creator/JohnVarley (and the movie based on the book), it takes time for the temporal paradox and catastrophic breakdown of the fabric of time to reach the present (our future), thus giving the hero time to try to avert it. These waves can even be detected, giving the future a chance to buckle down.

* In the 1983 novel ''Millennium'' by Creator/JohnVarley (and the movie based on the book), it takes time for the temporal paradox and catastrophic breakdown of the fabric of time to reach the present (our future), thus giving the hero time to try to avert it. These waves can even be detected, giving the future a chance to buckle down.

This doesn't make intuitive sense, but then again, time travel generally doesn't. It is fairly common, though, for changes to [[TravelingAtTheSpeedOfPlot Travel at the Speed of Plot]] — for example, some "bad" change that sets up a crisis to take days or hours to hit the heroes, while the "good" change that resolves it propagates instantly. Sometimes, the ripple is portrayed as propagating through time. For example, the wave hits a certain time. [[TimeyWimeyBall Ten minutes later]], the wave hits ten years in the past.[[note]][[DontExplainTheJoke One would expect the wave to hit ten minutes in the future, ten minutes later. It would already have hit ten years in the past, ten years ago.]][[/note]]

* This is the main plot of the first ''Anime/TenchiMuyo'' movie. Tenchi's mother is somehow killed in the past, and to keep Tenchi from vanishing in a week (when [[MadScientist Washuu's]] technology can't protect him any more), he and the gang travel back to figure out what happened and prevent it.

* In the ''ComicBook/StrontiumDog'' "Max Bubba" story, as Bubba alters the timeline, scientists 1400 years in the future actually measure the rate and degree at which time is changing. It doesn't make any sense.
* In a ''ComicBook/FantasticFour'' arc, Franklin and Valeria Richards (Reed and Sue's kids) come back from a BadFuture where all of reality is collapsing to try changing things so that won't happen. Upon their return, they don't know if it worked. Something changed, but the new future is "still 250 years away" and won't get there before Franklin can't keep control any more and everything implodes.
* Present in ''ComicBook/PaperinikNewAdventures'' in one particular instance, where an event in ''the future'' would cause a TimeCrash if not stopped.
* In ''ComicBook/LastDaysOfTheJusticeSociety'', the destruction of the universe in 1945 due to Hitler linking the fate of the Norse gods' Ragnarok to that of the universe also takes time for it to have the full effect on future history, as just after Dr. Fate shows the ComicBook/JusticeSocietyOfAmerica what the Spectre witnessed had happened in 1945, the same "rip in the sky" effect also appears in the present time (1985). Since the event also happens after ''ComicBook/CrisisOnInfiniteEarths'', the Golden Age versions of Superman, Batman, and Wonder Woman still appear in the past, as changes in the ComicBook/PostCrisis timeline have not yet taken effect and wouldn't take effect until ''ComicBook/AllStarSquadron'' issue 60.

[[folder:Films — Animation]]
* In ''WesternAnimation/MeetTheRobinsons'', the changes made by the bowler-hatted man visibly ripple across the future, ditto for when Lewis reversed those changes. In fact, a scene is devoted to Louis giving the Bowler Hat Guy a tour of the restored timeline, repairing itself at an extraordinarily slow rate. On the other hand, Lewis's decision to never make Doris should have reversed things then and there, but it didn't happen until he faced Doris and told it so. Doris vanishes instantly.

[[folder:Films — Live-Action]]

* Practically [[InvokedTrope invoked]] in ''Series/WhereInTimeIsCarmenSandiego'', where [[TimePolice ACME TimeNet]] has 28 minutes to recover and restore the object of Carmen's latest theft before history changes permanently. This is a generous time frame considering the time between an episode's start and the loot being restored is roughly 20-23 minutes.

%%* The PBS game show version of ''Series/WhereInTimeIsCarmenSandiego'' is based around this trope.

** In general, changes to history affect the future in three distinct waves: First, there are "time quakes", disturbances in the fabric of space-time that can alert specialized computers to historical changes, but which otherwise have no effect on the present. Next, physical objects will change to match the altered timeline; people killed in the past will suddenly wink out of existence, and works of art or science inspired by the time travelers will suddenly appear. People's memories are the last things to change; even the Time Masters can't predict how long it will take for this to happen, and some people retain subconscious memories of erased timelines permanently.

* In ''Disney/MeetTheRobinsons'', the changes made by the bowler-hatted man visibly ripple across the future, ditto for when Lewis reversed those changes. In fact, a scene is devoted to Louis giving the Bowler Hat Guy a tour of the restored timeline, repairing itself at an extraordinarily slow rate. On the other hand, Lewis's decision to never make Doris should have reversed things then and there, but it didn't happen until he faced Doris and told it so. Doris vanishes instantly.