Excepting mundane travel from the past to the future at a rate of one second per second,note note no human has ever experienced Time Travel first hand. Indeed, we don't know if it's even possible.note So debating which time travel theory is right is much like trying to find the best flavor of Kool-Aid. Fans are aware and accepting of this, just like no one minds when Our Monsters Are Different, or two different series have different rules for magic, so long as the series' own internal rules are consistent.
Of course, sometimes they aren't. The Timey-Wimey Ball is the result of a series or movie where the writers are a wee bit confused or forgetful about exactly which kind of time travel can happen, sometimes within the span of one episode! One day You Can't Fight Fate because You Already Changed the Past (or at least not without the Butterfly of Doom or Clock Roaches coming along), but the next you can Screw Destiny and Set Right What Once Went Wrong by killing Hitler and changing the past for the better. Especially headachy because there's no Temporal Paradox, or if there is it's totally arbitrary.
The standard Hand Wave (if one is given) is that time is very complicated and the particulars of the situation affect how the rules apply in ways that a layperson wouldn't understand. Which is one of the many reasons why some fiction fans really, really HATE time travel.
Despite the similar images the name might conjure, this is unrelated to Swirly Energy Thingy (although a Swirly Energy Thingy might very well have Timey-Wimey effects). Likewise, a Continuity Snarl is not necessarily related, though the presence of Time Travel-induced retcons can certainly make a character's past seem like a tangled up ball of yarn.
Compare Close-Enough Timeline. Occasionally, anything involving this may decide to pull out the Temporal Paradox card, and/or The Multiverse. A Time Crash is what happens when this isn't in play. See also Narnia Time. Aside from shape, unrelated to ball-shaped behavior tropes. You had better hope it is unrelated to Happy Fun Ball.
Warning: High chance of spoilers.
- DokiDoki! Pretty Cure's Non-Serial Movie handles this trope in what's probably the most dumbest way possible. The Big Bad, frustrated at the Pretty Cures escaping their temporal prison as well as reforming one of his minions, decided to travel to the future and kill everyone there. Apparently, according to this movie, if there is no future to look forward to, the present will cease to exist (despite the fact that going to the future and changing things there affects jack squat in the present). It's telling that when the next time Pretty Cure decided to handle time travel again in HuGtto! Pretty Cure, they opted to scrap what DokiDoki established in exchange for doing something similar to how Dragon Ball handles time travel.
- Dragon Ball Super can get into this in the "Future Trunks" arc. Previously in DBZ, Trunks' time machine worked firmly on alternate time line theory. DBS sticks to that rule.. for that time machine. It then introduces divine time travel through the time rings, which works on Stable Time Loop, as do any actions done by the gods using divine ki. However the time machine and time rings are both active, and each can only do its own version of time travel. It gets confusing very quickly.
- For a more specific example that set off the entire plot: Trunks time-travels to the alternate past he created to get help against Goku Black. Black temporarily follows him and has a brief fight with regular Goku. Beerus and Whis, who were spectating, notice a similarity between Goku Black's ki and that of a Supreme Kai apprentice in universe 10, Zamasu. While they're investigating, Goku spars with Zamasu to find out why their energy is so similar. Zamasu really wasn't the most stable individual to begin with, and his defeat pushed him over the edge and prompted him to kill his master Gowasu to obtain a time ring, then use the Super Dragon Balls to swap bodies with Goku and then terrorize Future Trunks' timeline as Goku Black, which prompted Trunks to go back in time. Beerus and Whis then go back to creating alternate timelines by destroying Present Zamasu before he could kill Gowasu (the Time Ring prevented Goku Black from being erased by this) and warning the Beerus of Future Trunks' timeline about Zamasu's plan before it could happen, respectively.
- Fairy Tail:
- The Memory Days OVA features a plot where a magical book sends Natsu's team back six years in time for a few hours, creating a Stable Time Loop where they influence events from their past (Natsu getting the scar on his neck, and Lucy deciding to join Fairy Tail).
- Things get really complicated with Eclipse, a gate created by Zeref that enables Time Travel. Hisui plans to use the gate to travel 400 years back in time to kill Zeref, which would create a Temporal Paradox as Zeref would never have concocted the idea. This leads to a Bad Future where an army of 10,000 dragons in the past comes through the gate, and so Lucy uses the gate to stop this from happening. However, this creates a second Bad Future where Acnologia takes over the world seven years later, and so Rogue travels back to the day before Future Lucy arrives so he can stop Present Lucy from closing the door, resulting in a third timeline (the main one). Destroying the portal in this timeline prevents Future Lucy and Future Rogue from ever using it, thus sending them and the dragons back to their respective time periods. At this point, however, the timeline has become so jumbled that the damage caused by the dragons cannot be reversed, and everyone in that timeline still remembers what happened. Moreover, one of the dragons from the past is also influenced to keep a nickname that was given to him in the present, while another's ghost clearly remembers them.
- Ultear's Dangerous Forbidden Technique, Last Ages, reverses time at the cost of the user's lifespan. She compounds the aforementioned timeline hijinks by using it to prevent them from happening at all, only for it to send her a single minute into the past. However, the spell gives everyone in the world momentary foresight of what would happen within that minute, which works in the heroes' favor, seeing how a good number of them were dying at the time.
- Eclipse comes back into play again (this time in a much stabler way) when it's revealed Lucy's ancestor, Anna, worked with Zeref to send Natsu and the other Dragon Slayers 400 years from the past through the gate. For this to work, Anna left specific instructions for her descendants to open the gate on the other side when the time was right, which was passed along until it reached Layla, Lucy's mother, on July 7, X777, a good 14 years before the above fiasco happened.
- Another concept of time travel is discussed in the form of Neo Eclipse, Zeref's ultimate plan, which would theoretically allow Zeref to relive his own life with all of his present memories intact so he can prevent his family's death, avoid becoming cursed, and stop Acnologia before he grows too powerful. Unlike regular Eclipse, which is all but stated to keep any alternate timelines it has created intact, this spell would completely erase the current timeline from existence.
- There's at least one Stand user in every arcnote of Jojos Bizarre Adventure capable of manipulating time (and at least one other that can predict the future but not travel through time). All of them seem to operate on slightly different rules as to whether or not the past and/or future can be changed.note
- The predictive Stand, Thoth, predicts specific events in the near future. No one, not even its user, can stop those events from happening, but they're always vague enough for Prophetic Fallacy to be in full effect; for example, it predicts that Jotaro would have his head split in half by an explosion, but the brother of Thoth's user disguised himself as Jotaro to avert suspicion and ended up being the one to be hit by an explosion. Of course, Thoth's predictions might not be so malleable after all — Jotaro dies onscreen twice in future parts, and both times his head gets split in half in the exact same pattern predicted by Thoth.
- In the next part, Yoshikage Kira's 'Killer Queen Bites The Dust' has the power to trap its victim in a one-hour time loop. Anything that happens in the loops will happen again in all subsequent loops, though the leadup to those happenings may be different; for example, when Hayato managed to stop the teapot from falling off the table, the handle of Kira's teacup broke a few moments later, spilling tea all over his jacket, and after Rohan triggered Killer Queen's bomb in the first loop, he still exploded in the subsequent loop even though he didn't trigger the bomb. However, if Kira ends the loops before they complete, events that should have been fixed no longer happen.
- In the part after that, Diavolo has the stand King Crimson, which is so infamously confusing that 'how does King Crimson work' has become a meme. First of all, King Crimson itself has a sub-Stand called 'Epitaph' that functions almost identically to Thoth, in that it can predict the future at a range of up to ten seconds, and the predictions it shows cannot be changed but are vague enough to be subject to Prophetic Fallacy. (This is seen in one story arc when Doppio is granted access to Epitaph but not King Crimson.) King Crimson's power, however, allows it to 'skip' those ten seconds, making it so that any unfavorable outcomes Epitaph predicts simply don't have to happen.
- Then there's Part Six, where Enrico Pucci eventually evolves his stand into 'Made in Heaven', which has the power to accelerate time. He uses this power to push the universe forward to the Big Crunch and recreate it. The new universe is exactly identical to the original, except that everyone living in it already knows everything that's ever going to happen to them and is unable to change it.note Only Pucci is capable of changing events, though once he's changed someone's fate, they are able to act freely, as anything they do from then on is considered a 'butterfly effect' repercussion of Pucci's actions.
- Finally, in Part Seven, Ringo Roadagain has the stand Mandom, which allows him to rewind time by six seconds. Unlike most previous time-travel arcs, Ringo can freely change anything that happens in those six seconds; he typically allows his enemy to deal him a mortal wound, memorizes their movements and position, then rewinds, dodges their attack, and kills them. He'd probably be the most formidable of all the listed users if not for the fact that everyone else can also remember what happened in the six seconds Ringo rewinds, and, if they're clever enough to figure out what his power is, can take advantage of it to change their actions as well.
- Mahou no Iroha: Time travel is apparently very possible with the help of magic, and the Magical Girl main character somehow changes some things but not others that leaves readers scratching their head.
- Natsu no Arashi! enjoys playing foosball with its Timey-Wimey Ball as characters jump back and forth across the hours, leading to a series of Stable Time Loops.
- Negima! Magister Negi Magi: Time travel watches pop up during the Mahora Festival arcs, creating Stable Time Loops, multiple copies of Negi running into each other, a Set Right What Once Went Wrong or two, and some Rule of Cool duels that exploit the effects of short-range Time Travel. However, it is later stated that long-range Time Travel creates Parallel Universes.
- Transformers Armada:
- After Thrust shoots Starscream with the Requiem Blaster, we see a shot of Rad as an eight year old waking up in his parents' car and asking tiredly where the Mini-Cons are (implying his "present" mind was momentarily in his past body). Then cut to all the kids — possibly in an alternate future — being told by a slowly dying Hot Shot that the Transformers have all been eaten by Unicron because they didn't know that the Mini-Cons were servants of Unicron and were led to their doom. After this, cut to the kids now being at the moment of the Mini-Cons' creation millions of years ago inside Unicron. Rad then touches High Wire's hand and frees him (and by association all the other Mini-Cons) from Unicron's control by reminding them of their past/future happiness together. The Mini-Cons then know to go to Earth after they leave Cybertron to meet Rad and the other humans. Cut back to the humans returning mere moments before Thrust shoots Starscream, whereupon High Wire and his teammates combine into Perceptor and knocks the gun away, causing Thrust to miss Starscream completely. And none of this is EVER EXPLAINED.
- The Mini-cons who prevented Starscream from being blasted weren't taken along with the kids' inexplicable time-jump, and there is no reason for them to have done anything differently in the present. It can't even be due to the kids' actions in the past — the Mini-cons would never have gone to Earth to kick off the events of the series if not for the kids, so it's not a case of the "old" High Wire wanting Starscream to die but the "new" one saving him.
- Tsubasa -RESERVoir CHRoNiCLE-: The fucking up of the entire time-space continuum. Trying to trace the law of causality after a case of Nice Job Breaking It, Hero would cause more brain damage than the combined screws of Quantum Mechanics, Relativity, and Superstring Theory put together! Just one of the results was a situation where thanks to incorporating every single type of Time Travel, you can't say if it is Always Identical Twins, Alternate Self, Identical Grandson, Generation Xerox, Cloning Blues, My Own Grampa, Tangled Family Tree, Everyone Is Related or a blow your brain combo of all of these put together simultaneously! Putting what is confusing about the time travel involved into words is, in itself, extremely confusing.
- There's a Back to the Future card game based on the film, where again each player is someone from an alternate timeline trying to manipulate the universe into one where they exist. However, one big difference is that after doing so, the time travelers have to stop Emmett Brown from inventing time travel so that nobody else can mess with it and their timeline becomes the only timeline. Paradox much?
- In Chrononauts, players are competing time travelers from alternate futures sent on missions into the past to recover various historical artifacts. Each player is playing tug-of-war with the timeline so that they can return home, which results in a very fluid history. If enough paradoxes pile up, they can even destroy the universe.
- In Time Agent, your objective is not to win. Your objective is to have already won... without Time Travel being invented. This is probably the least confusing part of the game.
- In US Patent #1 by Cheapass Games, each player has invented a time machine and hopes to profit from it, but the only one who will be able to profit is the one who holds a patent. Given that patents can be invalidated by proof of earlier work, the only patent that matters for a time machine is the chronologically first one. So the entire game consists of a race through time to be the first in line on the first day the Patent Office opens.
- Marvel Comics' Adam Warlock, specifically his evil future self The Magus embodies this trope. Adam Warlock met his futureself and immediately The Magus set about trying to ensure Adam would turn into him. This did not work when "Thanos" and the In-Betweener interfered and Adam was given a choice of timelines, wherein he chose the shortest. The Magus appeared again when Adam Warlock attained the Infinity Gauntlet and divested himself of his good self (The Goddess) and his evil self (The Magus). The Magus initiated the Infinity War, but was defeated. Later, to seal the Fault in space caused, in part by the Annihilation Wave, The Phalanx Invasion, and the War of Kings, Adam Warlock who, as he expanded magical energy slowly started turning into The Magus, used an "unused" timeline to repair the fault. That particular "unused" timeline was the one in which he became The Magus.
- The Avengers:
- Say the word "Kang" to a fan and they'll often shudder. His time-travel schemes are so complex that his future self, Immortus, is another major Avengers enemy, and the two can often be seen fighting each other. To give a sense of scale: most Marvel Handbook profiles are one to three pages long except for major characters like Spider-Man, Iron Man or Wolverine. Kang's gets six pages, and the bottom half of each page is devoted to Kang's timeline, which is chronological in years but requires jumping around from page to page to get Kang's chronological story.
- And his younger self, the Fantastic Four enemy Rama-Tut. Actually, Kang took on the Rama-Tut identity twice, and was villainous the first time and relatively benevolent the second time.
- Made even more confusing with the addition of a fourth iteration of Kang in Young Avengers: Iron Lad who actually kills Kang in an attempt to prevent himself from becoming Kang and ultimately realizes the only way to save the future is to become Kang anyway. If you find yourself confused, know at least that you aren't alone:
Jessica Jones: Is this a time-travel thing? Because I hate time-travel things.
Iron Man: If it's Kang, it's a time-travel thing.
Jessica: See, this is why I hate Kang...
- You can also thank Kang for raising one of the X-Men's greatest foes, Apocalypse.
- Kang's schemes also led to the temporally complex even of Avengers Forever, when Kang's attempt to prevent himself becoming Immortus led to a conflict which featured seven Avengers from six different time periods coming together to help Kang protect Rick Jones from Immortus and prevent humanity's darker possible futures (this team included Captain America from the end of the original Secret Empire storyline, Hawkeye just after The Kree/Skrull War, Yellowjacket during his initial mental breakdown, Giant-Man and the Wasp from Rick's present, and Songbird and Genis-Vell from what appear to have been possible futures).
- During Bendis' run on two Avengers titles he floated the idea that time is both like a living thing(which it technically is, embodied by the Sentient Cosmic Force that is Infinity) that occurs all at once and is damaged by time travel. These theories were hypothesized by Iron Man during conflicts with Kang after one time travel too many to change one moment and defeat Ultron broke the spacetime continuum and collided multiple potential futures and parallel realities with their present. This would be revisited (or recycled based on how cynical one is) during Age of Ultron where another conflict with Ultron involving too much time travel led to another crash. This time the effects were further reaching, where instead multiple people in parallel universes were struck dead and others still were permanently shuffled around the multiverse.
- The DCU has all sorts of fun here, especially when Booster Gold is involved, but it's been proven time and again that trying to Screw Destiny usually ends badly. Aside from that, the Timey-Wimey Ball hurts Booster's head as much as it hurts the audience's.
- DIE: The more that the party learns about the timeline of Die's world, the less sense it makes to them: Sol says he created Die, yet when the spirit of Charlotte Brontë appears, she says that she and her siblings visited it frequently as children after receiving a gift of toy soldiers, which we later find out that Sol carved from Angria's sacred forests after becoming Grandmaster. And further complicating things, there's the matter of Angela's daughter Molly, who shows up in Die as a Fallen and looking years older than the last time Angela saw her, despite them only being back in Die a few months.
- The Fair eventually explain that this is all because of a Stable Time Loop: Die itself is sentient and capable of reaching through time to ensure its own existence. It subconsciously inspired the various writers whose works contributed to Die's world, as well as Sol to create the game, and later as Grandmaster to create the toy soldiers that were sent back to Charlotte and her siblings, while Eternal Prussia is currently using the remains of Glass Town to create the six dice that brought the party to Die. As for Molly and the other Fallen, they've been brought back from a future where Die has merged with Earth, which it will do once it has completed the loop by sending the dice back in time.
- The Flash:
- Professor Zoom has (retroactively) had his hands on the Timey-Wimey Ball from day one. In a single issue you see him edit his brother, parents, scholarly rival, and lover out of his own history, apparently to make sure he'll actually become the supervillain he is. It Makes Sense in Context.
- The Return of Barry Allen presented an interesting example of this when the "Barry Allen" who had returned turned out to be a version of Thawne who personally hadn't even met Barry yet even though he was now in a time period where Barry had killed him years ago.
- When the Professor started in on Barry's history, that ended with Flashpoint. Nice job breaking it, psycho.
- The Flash himself historically averted this trope when at all possible. Barry and Wally repeatedly refused to even try holding the Timey-Wimey Ball. Until Flashpoint. Nice Job Breaking It, Hero.
- The second Zoom came into being because he tried to grab the Timey-Wimey Ball and blew himself up. Unfortunately for him, his powers (unlike every other speedster) avert the trope.
- An issue of Impulse had a Mad Scientist invent a time machine, and attempt to change the past so that he would rule the world. Impulse and Max Mercury go back in time to stop him, but wind up stuck in the far distant past. Max lectures Bart on the Butterfly of Doom, and how even eating a fish might cause irreparable harm to the future. But then they discover that the mad scientist is now trapped in the past as well. The three of them decide that the best way to get home is to cause as much damage and destruction as possible. Their logic is that if they completely change the past, it will alter the future so much that the scientist will never exist, which means he will never invent his time machine, which means they won't have travelled to the past in the first place, which means they won't actually cause any damage at all and find themselves back home. Confused?
- Professor Zoom has (retroactively) had his hands on the Timey-Wimey Ball from day one. In a single issue you see him edit his brother, parents, scholarly rival, and lover out of his own history, apparently to make sure he'll actually become the supervillain he is. It Makes Sense in Context.
- Gold Digger: With all the dimension-hopping, time-traveling technology in Gold Digger, naturally there's a lot of Timey-Wimey Ball action going on. However, of special note is issue #50 of the color series, which features an artifact that is an actual ball of string that can warp time and space.
- Invader Zim (Oni) parodies the complexity of time travel a few times:
- In Issue 12, Zim claims that his actions in the Bad Future changed the past. Dib quickly points out that that isn't how it works, only to be told to shut up.
- In Issue 49, Zim messing about with time travel causes all the alternate timelines accessed via the Zimvoid to merge together. Again, an exasperated Dib tries to explain that's not how it works, only for Zim to ignore him, as whatever he did still got the result he wanted.
- Iznogoud: In Iznogoud's Childhood, Iznogoud experiments a type of time travel in which the present and the past happen at the same time for a while, which he tries to exploit by attempting to get rid of the Caliph's younger self. The whole thing eventually ends up being a Stable Time Loop, in which Iznogoud's time travel is what causes his younger self (who Used to Be a Sweet Kid) to transform into the Jerkass we're familiar with. However, earlier in the comic, Iznogoud stabs younger Wa'at Alahf to test the time travelling nature, and that case works on a Ripple Effect basis, in which adult Wa'at Alahf shows up with a scar he'd never had.
- Legion of Super-Heroes. There's three of them. Two of their enemies are the Anthropomorphic Personifications of the Timey-Wimey Ball.
- A good instance of this happened in the Final Crisis side-story Legion of 3 Worlds. Superman, Saturn Girl, Lightning Lad and Cosmic Boy confront the Time Trapper (one of those two enemies above) and learn this incarnation (long story) is a future Superboy-Prime. When the Time Trapper and Prime meet, Trapper's insistence on getting Prime to listen to him causes Prime to get angry and slug him, causing a Never Shall The Selves Meet explosion that erases the Trapper and causes Prime to disappear. Saturn Girl worries they just broke their Thou Shalt Not Kill rule, but three different Brainiac 5s suggest that Prime just disappeared somewhere else in time/space instead.
- Sonic the Hedgehog (Archie Comics) has an interesting variation at one point. Knuckles, juiced up on Chaos Energy, was given the chance to bring back everyone on the Floating Island through his power. To do so, he keeps bouncing back in time and stopping a certain event. Not only does that have bad consequences for him, but what he doesn't know is that he keeps futzing up the actual Sonic events, creating timelines such as a pure SatAM world, one based off of the 1995 OVA and a timeline where Robotnik never initiated his coup. At the end, Knuckles decides to stop that and just bring everyone back from the prison the Dark Legion launched them into.
- Teen Titans Go!: In Issue #31, a villain changes Robin's past to become his mentor and the other titans are helped by Good!Robin's future self a.k.a. Nightwing. During the epilogue, Beast Boy wonders how that Nightwing could exist at the same time as Bad!Robin and Raven handwaves it by saying they don't fully understand how Time Travel works.
- Limbo in the Marvel Universe (mainly shows up in association with X-Men) is an entire dimension of timey-wimeyness. When the X-Men entered and got separated, both Wolverine and Colossus encountered long-dead versions of each other, and managed to escape just fine in the end. Storm was stopped at one point by her older self, who had remained in Limbo for decades studying magic. And Nightcrawler killed his older self.
- The Transformers (Marvel): One can alter the past to suit the present. However, there is also the possibility that one travels to a different universe that is simply the same as your own. So thus, any attempt to travel back in time to, say, build a giant cannon to destroy the dark god who created you when he turns his attention to Earth in order to free yourself from his control as Galvatron tried to, can potentially end in failure as it is not your own universe. As it turned out, it WAS Galvatron's own universe.
- John Byrne's run on Wonder Woman Vol 2 has a classic example of the rules changing within a story. When Diana's mother becomes the new Wonder Woman, Jay Garrick recognises her as the mysterious woman who was involved in one of his adventures in The Golden Age of Comic Books, and who he never really met. When he tells Hippolyta this, she travels to the past in order to maintain the timeline by ensuring everything happens the way Jay remembers. Once she gets there, however, she decides to stick around and become the Golden Age Wonder Woman and a member of the Justice Society of America. History is therefore completely altered after all, but no-one seems to mind.
- All-New X-Men had a hard time deciding whether they were changing the timeline, creating a new one, creating several new ones, or just messing everything up OR whether it had all already happened. Both this book and the tie-in Battle of the Atom had the added conundrum that while people from the past who were still alive in the present (and one who was dead in the present) were visiting the present, so were a bunch of people from the future, at least one of whom was presently visiting from the past. Several times.
- Zipi y Zape: All the story about the time-travel machine built in a barrel revolves around this trope. In the first chapter, the twins use it to transform a wall lizard into its evolutionary ancestor (which turns out to be a crocodile). In all the other chapters, the twins use it themselves; it no longer makes anything appear in the present time, but depending on the chapter, it either just takes them to the past, or somehow transforms them in their ancestor (and, somehow, with all the knowledge and remembrances that those ancestors have). In one chapter, when their mother makes an omelette with an egg found in the past, the twins remark that its strange look is due to the fact that the egg had over two hundred years, even though the time travel should have prevented the egg from aging. Finally, in the last chapter, the twins get trapped in the future when their machine gets broken; strangely, in a rare example of an inverted San Dimas Time, it's said that house prices were getting higher because of the twins' absence.
- Discussed at length in The Parselmouth of Gryffindor: time-travel magic only exists thanks to a loophole in the rules of the universe, and so while theoretically it ought to allow you to change the past, in practice, magic does its best to manipulate probablity so that the result is a Stable Time Loop. The farther back in time you go and the more efforts you make to change the past, the more unstable space-time becomes until you're either obliterated or kicked back to your home time period.
- Child of the Storm features Doctor Strange, an expert time traveller who was altered by the Time Stone when he was younger and has spent all his extremely elongated lifespan (roughly 500,000 years and counting) manipulating history to the very specific end of defeating Thanos. As he becomes more prominent in the sequel, it's occasionally noted that time travel is extremely complicated - the general consensus is that you can change the past, but it's not easy and you really have to know what you're doing - and Strange generally declines to explain for two reasons. One, being cryptic and enigmatic is kind of his thing. Two, he dislikes "explaining temporal physics to neophytes". This is an audience, by the way, that includes Odin (though compared to Strange, when it comes to time travel, even Odin is a neophyte). When Thor takes umbrage at this, Strange (who is over 300 times older than Thor) snaps that he should be glad that Strange isn't calling him a child.
- In Harry Potter and the Methods of Rationality, the time turners are used much more frequently, which leads to this when two or more are involved. Dumbledore and Snape have to resort to charts.
McGonagall: Tell me your conclusions, but please, don't tell me how you figured it out.
- This is actually an inversion, or something. The writer doesn't appear to be confused about what kind of time travel is possible; rather, he works very hard to make sure that it follows consistent rules. And the characters know about these rules. But trying to work out the logical implications of these rules results in confused characters and confused readers.
- Trying to find loopholes in the rules has been shown to result in leaving angry notes for your past self not to do so.
- Kyon: Big Damn Hero has much more Time Travel going on than the original — to the point that at any point of story there is at least one open loop. Amusingly, Kyon once quoted the Doctor when trying to explain his understanding of Time Travel.
- In the Mass Effect's Crucible, the multiverses work mainly as "Overwriting the timeline" but later the CrucibleVerse itself become a hybrid version of both "Overwritting" and "Branching timelines". Basically, time can be seen as a river with different universes as balls floating in it. Each ball has in front of it what look like millions of almost identical versions of itself in different points spread across the width of the river while behind there's nothing. As the ball floats forward depending on how the river flows it'll take the place of one of the many copies and the others in line with it disappear. The potential what might have been's all disappear when the ball finally arrives. So as the future hybrids come to the present of the CrucibleVerse and change it, the Bad Future soon disappear to be replaced by a new future.
- But due to Sam, Aunties and their "employers"'s intervention, a new future, different CrucibleVerse is created by pulling the bad future backwards and, as it can't survive on its own, branching off from the main timeline like a Siamese twin. In new time line, the souls of those time travellers from the Bad Future are put into their younger bodies while alt.Jane meet her main counterpart to know everything that happened in the now disappeared bad future to change the new twin universe for the better. This also cause Life and Death from the main timeline to work double-duty since they partly exist outside of time and space.
- Two for the Price of One sees Leonard Snart being brought back to life after his apparent death at the Vanishing Point, and when Barry and his allies mention the time they recruited Snart's help in "Infantino Street", the Legends realise that the Snart Barry recruited was a future version of Snart; they speculate that Snart implied he was a younger version of himself either to avoid mixing up the timeline or just to screw with the Flash's allies, and Snart admits that both are likely to be true.
- In My Immortal, the main character Ebony travels back in time to teach a young Voldemort about love. But when she does, the plot really starts to get strange. A few examples are that characters in the past know what will happen in the present, that items will not work in time-periods where they're not invented yet, and that people can't die outside their native time-period.
- In Castle fic "Flashforward", Kate Beckett of 2012 swaps places with her 2009 self, but when she attempts to follow up on the leads she's found on her mother's case in the future, she is killed by Senator Bracken's assassins, her death in 2009 erasing her 2009 self in the future and creating a timeline where America is on the brink of war with China. Fortunately, a time-travelling agent (employed by the organisation featured in "Time Will Tell") is able to recruit the Castle of the new 2012 and send him back to save Beckett's life, which results in a new version of 2012 where Montgomery survived his retirement and was able to provide information to confirm Bracken's role in Johanna Beckett's death in exchange for immunity for himself.
- Infinity Crisis;
- In Salvation Run, Mia Queen was actually Laurel's daughter rather than Felicity's, and also observes that the Snap never happened in the history she and Nora experienced.
- In All Kinds of Legends, a younger Vandal Savage is displaced from his universe into the reality of the League of Extraordinary Gentlemen, and is opposed by the Legends of Tomorrow after they have killed his future self but before he has even met them.
- In Skysurfin' Surprise, the Seventh Doctor and Ace are also revealed to be tracking the dimensionally-displaced Skrulls, despite previous stories depicting the Thirteenth Doctor as taking an active role in the investigation. Batman Family also adds the Eighth Doctor to the mix, with this version apparently pre-Time War and aware that both his past and future selves are investigating the crisis at other ends.
- The Star Trek: Voyager fic "Facets" is basically an expanded version of "Shattered" which goes into further detail of Chakotay's search of the ship's history, such as featuring Kes taking part in the final confrontation in Engineering or Janeway and Chakotay meeting an eight-year-old Miral from a timeline where Tom Paris became Captain after their deaths. At one point, Janeway and Chakotay find themselves in a frozen corridor with the body of an ensign that Chakotay knows died a year in his relative past, thus preventing the corridor being from a possible future, but only the reader is aware that the corridor originates from the alternate future erased in "Timeless".
- The Charmed (1998) fic "Tempus Fugit" opens with Paige and Henry surviving the final battle and going back in time to save Piper and Phoebe, only to overshoot and end up going back to the moment when Prue was killed by Shax. Paige sacrifices herself to protect Prue, only surviving long enough to cast the vanquishing spell to defeat Shax, but the Elders subsequently merge Henry with his past self, and Paiges spirit evades the Angel of Death and does the same with her own younger self, allowing them to retain their memories of the future (although Henry naturally only knows what Paige already told him about the past and Paiges memories are fragmentary).
- In the Power Rangers fic Power Rangers Mythos, after the alchemist Avanth destabilises the Morphin Grid of the year 2600 and kills most of the active Rangers, the last surviving Ranger, Fae the Yellow Ranger, must resort to desperate measures and use a time machine to recruit past Rangers to use the only remaining active Morphers to oppose Avanth. As a result, she recruits a new team of Rangers from different time periods, including Tommy Oliver during his time as the Green Ranger (Mighty Morphin' Power Rangers), Z Delgado (Power Rangers S.P.D.), Flynn McAllistair (Power Rangers RPM), Shelby Watkins (Power Rangers Dino Charge) and Adam Park (Mighty Morphin Power Rangers in Tommy's relative future).
- In the Titanic (1997) fic "Our Future is Now", Jack and Fabrizio reveal that they are actually time-travellers who came back to observe the lower-class passengers, but other parties come back to change history in a manner that leads to the Titanic never sinking. Rose is initially disturbed when Jack's explanation includes the revelation that, in a timeline where he was never on the ship, Rose would have drowned in Cal's stateroom, but after she decides to join Jack in the future, she is curious to learn that history still records the Titanic as having sunk. Jack explains that the time-travel method he used basically sent him into a different reality from the one that he and Rose are living in now, with the result that Titanic still sank in their current reality even if it didn't in Rose's original reality.
- In "Peter Pan's Got Kids?", the events of Hook become more complicated when a child version of Peter Pan appears in Neverland at the same time as Peter Banning; when Hook inflicts a wound on the younger Pan's shoulder, the same wound appears on Banning, suggesting that the young Peter is Banning's past self somehow displaced in time. However, after Hook's defeat, Tinkerbell explains that the young Peter comes from a separate timeline and his future is not automatically going to be to become Banning; the 'simultaneous' wound was just the result of their timelines briefly intersecting rather than a guarantee that they were the same version of Peter Pan.
- In "Spider-Man: A Way Back Home", Gwen Stacy of The Amazing Spider-Man Series finds herself in the Marvel Cinematic Universe after the events of Spider-Man: No Way Home. Once Peter Parker (of the MCU) meets Gwen and works out where she comes from, he speculates that she came to his world because the three Peters curing Lizard and Electro of her world caused a subtle butterfly effect that changed the exact circumstances of Gwen's death.
- The Star Trek: Voyager fic "Stalemate" sees Ambassador Chakotay of the future depicted in the novels arrive on Voyager during the events of Endgame (written before Janeway was brought back to life by the Q). Despite the fact that the presence of Ambassador Chakotay should essentially negate Admiral Janeway's timeline, the ship is still visited by Admiral Janeway as it was in canon, the two future visitors spending some time together before Chakotay's death.
- In the Marvel Cinematic Universe fic "The other side", where basically the other half of the universe survived the Snap, when the new group of heroes attempt the "time heist" to retrieve the stones, they are able to recover the Soul Stone by arriving on Voromir at the moment that Steve Rogers of the canon timeline arrives to return the Stone used in Avengers: Endgame, allowing Peter, Wanda and Stephen to essentially borrow that Stone without needing to sacrifice anyone.
- Discussed in the Aladdin fic "A True Prince", where Genie interprets Aladdin's wish to be a prince by literally rewriting history so that Aladdin is now the prince of a neighbouring kingdom of Agrabah rather than just being dressed up to look like a prince. As a result of this change to history, while Jasmine now has no memory of Aladdin before he sneaks into Agrabah "in disguise" to meet her as he did originally, Jafar still retains some form of recollection of events, as Aladdin could have only acquired the lamp to make his original wish if Jafar led him to the Cave of Wonders in the first place, even if Jafar can't remember the exact events.
- In the Marvel Cinematic Universe fic "live not on evil", Wanda Maximoff's attempt to change history to save Vision and Pietro results in Peter Parker being sent after her by Doctor Strange, 'chasing' her through an alternate timeline. During Peter's attempt to catch Wanda, a series of out-of-sequence encounters with the Avengers of this timeline result in Peter bringing Vision back to life with the Soul Stone, blocking Nebula from linking up with her past self while on Morag, and providing Clint and Natasha with the Soul Stone on Vormir without anyone needing to sacrifice themselves. Most paradoxically, many of these meetings are only possible due to Peter being told he would do that by someone before he's done it but after the other party has experienced it.
- In The Power of Seven, after Voldemort abducts Harry and traps him in a comatose state for a few weeks, once he's rescued, Susan, Katie and Fleur put aside the idea of each waiting to bond with him over the course of the next few months (the ritual requires a full moon to be performed properly) and decide to do it all at once, using a time-turner to go back so that they can perform the rituals all at once and then rejoin the assault on the Death Eaters' base with no apparent time lost.
- On top of the above, Katie arrives at the moment of her bonding with Harry to find a future version of herself already there to give Harry a Twin Threesome Fantasy with both of them, with the Katies' words suggesting that Katie will only do that because she found herself with Harry when she arrived.
- In the Angel fic Impact, while waiting for Darla to give birth (Offspring), Angel Investigations are attacked by a Time Demon- a unique species charged with the responsibility of maintaining the flow of time- who attempts to kill Angel by using its weapon to switch Angel with the human version of him from I Will Remember You, only for Cordelia to intercept the blast herself. Back in 1999, Cordelia wakes up at the moment that the Day was reset (she speculates that she arrived before Angel changed history and just doesn't remember it after the reset), and a later confrontation with the Time Demon establishes that the idea of alternate selves is inaccurate, with the result that the Time Demon could have killed the future Angel by killing his displaced human self. At the fics conclusion, Cordelia is returned to the present after sacrificing herself to save Doyles life, and after an initial period of confusion regains all memory of the new timeline, where Angel Investigations defeated many of their original threats with the aid of notes left by the future Cordelia, Cordelia recognising that these new versions of her friends are still the same people just adjusted to new circumstances.
- A Crown of Stars tries to avert this. Daniel and Rayana explain Shinji and Asuka that they technically can stop Second Impact and other tragedies... but then Shinji and Asuka would be completely different people, ergo their fixes would be meaningless. So both gods use time-travel to undo the consequences of those tragedies.
- In Once More with Feeling Shinji remembers everything what happened in the original timeline, even though a lot of events are significantly different due to his actions.
- In The Second Try, Shinji and Asuka set to avert Third Impact, even though it'd mean that their beloved daughter will never be born. In order to avoid this, Kaworu sends Aki back in time, but she arrives several months later than her parents.
- Thousand Shinji: The Warhammer 40,000 gods changed the past so they never existed. Even so, Chaos Marine Khenmu and his brothers-in-arms keep existing, and the fragments of the gods still existed and remembered the original timeline.
- "Brother on Brother, Daughter on Mother" attempts to make some sense out of the trope as it applies to Star Trek (with the obligatory Shout-Out to the Trope Namer) with a variant of the many worlds theory wherein time is actually a rope made of strands of probabilistic outcomes that can tangle up. The purpose of the Time Police is to prevent that rope from "fraying" due to major temporal incursions; smaller incidents are usually papered over by the inertia of time itself.
- In the Harry Potter fic "For Want of an Outfit" time turners that aren't in use have a tendency to rewind themselves through time to a point where somebody will find and start using them. As they often travel much further into the past than they should be able to, they end up breaking their Stable Time Loop in the process and can send multiple copies back at once. Hogwarts at one point had twelve time turners produced by only three originals.
- The time travel in About Time appears to have at least two different modes, but the explanation is very scanty. Tim can go back to a previous occasion and change what he did, but then he can choose to either live from that point onwards, or snap forward to where he jumped from and see what the changes have been. The event described in Secret-Keeper seems to suggest he can also undo these changes.
- The whole messy issue of Time Travel is lampshaded in Austin Powers: The Spy Who Shagged Me when, after Austin starts to get bewildered by all the possible paradoxes his traveling into The '60s involves ("Oh no, I've gone cross-eyed."), Basil jumps in with "I suggest you don't worry about that sort of thing and just enjoy yourself", and then turns pointedly toward the camera and remarks "and that goes for you all as well". Much self-contradictory timey-wimeyness ensues since, as Mike Myers puts it in his DVD comments, "our theory of Time Travel is that Time Travel works however we need it to work for each particular scene's joke."
- Although, ironically, the conversation that confuses Austin doesn't actually contain any inherent paradoxes; the Doctor Evil he was chasing was the contemporary version who had also gone back in time. Past Doctor Evil and Past Austin were both frozen cryogenically during the time period in question so there would be no crossover.
- Discussed in Avengers: Endgame which introduces time travel as a way to get what is necessary to reset its predecessor's Downer Ending, and at least twice Banner complains about people thinking time travel works the same way as in the movies. It's explained that instead of creating paradoxes, altering the past would create Alternate Universes with no effect on their own but the Avengers didn't simply want to leave other realities for dead by keeping their stones. Despite this the Avengers inadvertently end up creating at least three alternate timelines; one where instead of Loki and the Tesseract being returned to Asgard after the Battle of New York, Loki uses the Tesseract to escape the Avengers' custody while Cap learns Bucky is alive early and HYDRA now thinks Cap is on their side, one where Thanos and his army died in 2014 around the start of Guardians of the Galaxy, and during his trip to return the Infinity Stones to their original locations, Captain America manages to live the life that he originally couldn't with an alternate Peggy Carter.
- Or to confuse things further, a Captain America from another timeline created the entire MCU by staying in the past and making a life with Peggy on the trip back to return the stones. Assuming every Captain America gets that same idea, it's as close to a Stable Time Loop the setting's time travel can accommodate.
- Back to the Future has different things happening to the hero as the past is changed. Read the timeline for the trilogy at this page if you have any questions about how it works. There isn't a single concern here that isn't covered there one way or another. To summarize, you can create alternate timelines, and any time it seems You Already Changed the Past (like Chuck Berry hearing the song he would later write) it's really just causing the same event in a different way (in the original timeline Chuck Berry did come up with the song entirely by himself).
- Ben 10: Race Against Time includes a bit of this. Eon seeks to use the Hands Of Armageddon to bring his Dying Race to Earth to repopulate, but traveling through time so much has weakened him to the point where he's unable to use the Hands. His plan is to use the Omnitrix to turn Ben into himself (a second Eon), so that he can activate the device and end the reign of humans on Earth. The movie is pretty vague about how it works, but at first glance, it seems as though Eon may actually be Ben, corrupted by himself in his own past. On top of that, when Eon succeeds in implanting himself in the Omnitrix, he declares that "two cannot exist at once", disappearing into a different point in the time stream.
- Bill & Ted's Excellent Adventure establishes that "the clock is always running in San Dimas" — that is, that however long Bill and Ted are in another time, that much time will have passed when they return to their "home time". This is held up for the first film and most of the second... and then utterly discarded for the ending of Bogus Journey, where they zap away for 18 months and return seconds after they left. Of course, the first film kludges it a bit as well — when initially going back to their own time, they actually end up at the same point they left, and have to be told by Rufus that they need to dial 1 digit higher for the next day. Even more odd, Rufus never tells the two of them his name. They hear it from their future selves, who presumably heard it from their future selves who...
- The Butterfly Effect has the events of roughly half of Evan's blackouts caused by his older self going back to them, while the other half were normal initially, but could be changed by his older self. One blackout even has examples of both. Also, it is established early on that Evan is the only who has any memory of the old timelines, but at one point another character notices a change in the timeline for no apparent reason.
- Déjà Vu (2006) starts out well enough, but implies that the detective has already gone back in time and failed. In the original timeline, the love interest dies, and the hero's blood is all over her apartment. So apparently, in the original timeline, he went back and failed. But then in the new timeline, he gets his wounds saving the love interest. He doesn't bleed all over the love interest's place until after he saves her. So how did there end up being blood in the original timeline, but the love interests dies? What's more, the ending finishes without a Stable Time Loop of any kind, so either the changes made will reset or they've created one alternate timeline where everything is hunky dory and one where everyone's dead.
- The time travel model used for this movie actually does make sense, it just creates convoluted timelines and is pretty confusing when watched without knowing this beforehand: https://en.wikipedia.org/wiki/File:Deja_Vu_Timeline.GIF#file The authors were pretty unhappy with the way the material was directed, saying that it made the film seem like it had many unforgivable plot holes even though there weren't any.
- Detention has one of these as a result of several things: a mother and daughter undergoing a "Freaky Friday" Flip that sees the daughter transplanted into her mother's body circa 1992, another kid from the year 1992 undergoing a nineteen-year time warp to the present day (2011), and a nerdy Asian kid in the present day transforming the school's bear mascot into a time machine for a science project. Ultimately, it will result in the destruction of the world... actually, just the destruction of Grizzly Lake High School, because hey, it's not like the main characters know of a world beyond high school.
- Frequency is very inconsistent with the way Time Travel works across the film. The movie initially suggests that there are two separate timelines, with a major character (John) in the present gaining memories of two separate timelines at the moment he changes history and saves his father. However, this is dropped afterwards, and the rest of the film suggests that he only has his memories of how events originally occurred. Perhaps more bizarrely, the climactic ending (happening in the two eras simultaneously, as both John and his father fight off the Nightingale Killer) suggests that events in one era will instantly cause timeline alterations to the latter — during the final fight, Frank shoots off the Nightingale's hand during a Hostage Situation. In the "present day" of 1999, the same individual watches his own hand twist and collapse down into a stump, which shouldn't be possible in the first place if his hand was shot off 30 years earlier.
- Hot Tub Time Machine is really inconsistent with its time travel mechanics. Four friends travel back to one day in 1986 and hijack their younger bodies, so everyone sees them as their younger selves. Except one of the friends - Jacob - wasn't born yet and looks the same in the past as he did in the present, and can also interact with the past, but whenever something happens that might possibly stop his conception he flickers out temporarily. Initially the friends, fearing the Butterfly of Doom, try to enact a Stable Time Loop by making sure the big events they remember from that night still happen, but then they change their minds and try to make sure the night goes better the second time around. Some of the big events they remember still happen no matter what they do, but not in the way they remember them. Other events they really do alter. Meanwhile they directly or indirectly cause a couple of historical changes. In the end Lou decides to stay behind and use his knowledge of the future to greatly improve his and everyone's lives. When the other three friends get back they all have much better lives but do not remember them.
- The Lake House was a horrible mixture of Time Travel ideologies. In some ways the timeline is constant — the guy she kissed at the party turns out to be the guy she's communicating with in the past. Yet in other ways the timeline is variable — she tells him how she misses the trees, so he plants one at the place she's going to live at — which she magically doesn't notice having grown until after she sent him that letter. And then there's the grandfather paradox involving the (lack of a) car accident at the end/beginning of the film, causing her to go/not go to the lake house and end up communicating/not communicating with the guy in the first place. And there's also the dog in the past timeline who responded to the name given to it in the future timeline.
- If you injure the present version of someone, the time-travelling-from-the-future version of the person will immediately show the scars. However, all events involving the future version up until the point the present version was injured continue to have happened as if the injury had never occurred. So you can cut off a present versions legs to stop the future one from escaping, and the future version will immediately fall over in a location they never could have reached unless they had legs up until a few seconds ago.
- The trope is lampshaded on several occasions by the protagonists; criminals who don't really understand how the various time travel paradoxes work, only that trying to sort it out in their heads just gives you a headache.
- Subverted in the extended version of the diner scene which is included as a DVD extra: after telling Young!Joe that he's not going to try to explain the effects of changing the past, Old!Joe then proceeds to explain them, using a line of salt — and it actually sorta makes sense.
- Lost in Space contains a plot where John and Don walk into the future by means of an energy field just to find future Will and Dr. Smith creating that energy field as a means to build a machine to travel into the past, because the entire family was wiped out as a result of John and Don disappearing by walking into the future. When present Will and Dr. Smith enter the bubble, nothing happens to their future selves. Hell, Future Dr. Smith killed his past self without a second thought.
- Time travel in Men in Black 3 varies between Temporal Paradox (the plot starts off with history being altered so Kay died in the 60s), You Already Changed the Past (Jay's father turned out to be have died in the process of Setting Right What Once Was Wrong), and Mental Time Travel (Jay defeats the Big Bad by rewinding time to avoid the attacks he can now see coming) depending on the needs of the plot.
- Project Almanac begins because David finds a video of his current day self at his seventh birthday party, which leads to him discovering and rebuilding the time machine stored in his father's basement, suggesting a Stable Time Loop. Immediately after doing this, however, the cast wantonly screws with their own timeline to make things more favorable for themselves, clearly demonstrating that time can also be changed at will. What's especially crazy is that the situation the video depicts is David retgonning himself by destroying the time machine, which he succeeds in doing, meaning the very situation that led them to the time machine originates from a timeline in which said machine does not exist.
- The film version of A Sound of Thunder (if not the book) uses hilariously inconsistent rules of time travel (and those rules don't make much sense before they start breaking them). It's a crucial plot point that the characters keep returning to the exact same point in time, but never run into previous versions of themselves (no explanation for that is given)... until the time they do (no explanation for that either). Plants smash through the walls of a building because the past was changed in such a way as to cause plants to grow larger and more aggressively (no explanation is given as to why someone decided to build the building in the spot where, in the new timeline, a giant tree has been growing for ages — not to mention why the tree that's always been there smashes through the floor while people watch instead of just appearing as it if had always been there). At one point, the characters are unable to travel back to the point in time they want to reach because there's a time disturbance between the present and their destination in the past; the solution? Travel back to an even earlier point and then go forward (if you guessed that no explanation is given as to why the time disturbance is somehow not blocking that too, you've been paying attention).
- Star Trek (2009): Word of God has it that instead of erasing the later series, it just split off a new timeline, so that the later series still happened in the original timeline (dubbed "the Prime" timeline in Fanon) but has not in the new timeline. This gets weird as there are many instances of characters from the Prime timeline traveling back to before the split, which means that if a character from the alternate timeline were to travel back to say, The orbital Atomic Accident, The Bell Riots, or The first Warp Test they would find time travelers from the Prime timeline, which from their point of view doesn't exist. Quite a Mind Screw... or Ass Pull, depending on the variance of your mileage. Prior to the film, Star Trek was pretty consistent that time travel changes affect the existing timeline, they don't spawn new timelines (though the existence of parallel but different realities were established, they just weren't caused by time-travel).
- Star Trek: Generations, contains a nexus which can at once be described as a portal through time and simultaneously interpreted as a veritable heaven which may, in fact, act as merely a database containing the sentient thoughts of all who have encountered it. Kirk's visit to his past doesn't affect the timeline (although one may say this is due to him not actually doing anything to affect it). Picard, on the other hand, experiences an alternate present. While all this could seem viable as time travel, Guinan stops by to mention that Picard can experience the past or the future, the limits of his experiences within the nexus seemingly being restricted to his own imagination. This should leave a very Fridge Logic-taste in anyone's mouth when they realize that Picard and Kirk traveling back to stop Soren may not actually be time-travel but merely a pocket of Picard's own imagination within the nexus. Thus everything that happens past this point in time (i.e. First Contact, Insurrection and Nemesis) are not actually part of the prime timeline as Picard is actually gone and the Enterprise is destroyed with its crew dead. Note that the new timeline Star Trek could still be viable as there's no mention of Picard or Enterprise D and Generations has no effect on Spock's existence. Basically, if you accept the nexus as a means of time travel then the time line splits. If you argue it as merely Nexus-Picard's mind, then it doesn't.
- Tenet: The titular secret organization has Turnstiles, machines that allow for time inversion and cause whatever passes through them to experience the flow of time backwards. The film is frequently vague with what the exact effects of inverting materials to send them into the past is like. For instance, inverted debris from a future war appears to have existed for centuries before the battle they came from, but in another scene the Protagonist starts bleeding from a wound his past self will give him in five minutes, which inexplicably pops into existence instead of always existing. The climax of the film also acts as though the Big Bad burying the MacGuffin in a specific place in the past will instantly allow his evil future bosses to instantly acquire it even though the heroes could easily prevent this by just digging it up in whichever year between the present and the distant future they wish.
- In The Film of the Book The Time Machine (2002), the Time Traveler discovers that he cannot change any part of the past that would interfere with him creating the Time Machine, since it would create a Temporal Paradox. He can interfere with other matters, such as when he goes even further into the future only to see the Morlocks victorious over the Eloi, and afterward returns to the year 802701 to successfully defeat the Morlocks.
- James P. Hogan had a solution in Thrice Upon a Time. The prospective time traveler induces a grandfather paradox. The universe doesn't abhor it or disallow it or anything, but simply plays out the umpteen zillion iterations of the events in question. A leads to B leads to Not-A leads to Not-B leads to A leads to B... It should go on forever, but on each run-through, quantum randomness causes things to be very, very slightly different (an atom decays or not, a pair of colliding air particle zig instead of zag) totally regardless of anything the time traveler does. Normally they won't make any difference whatsoever, but after a few million or trillion iterations, the randomness happens to align in such a way that it breaks the paradox (i.e., kills his wife in a new way) and lets the timeline continue past it. What we the audience see is merely the "final cut" version of history, the one that didn't get stuck in an endless loop.
- Time Chasers, which 99 percent of its viewers know from Mystery Science Theater 3000. It tells — or rather, tries to tell — the story of a man who invents a time-traveling airplane who has to repeatedly go back and stop his former boss from stealing and exploiting his invention for his own personal gain.
- 11/22/63 gets...vague with how time travel works. At first at seems like traveling to the past always creates a fresh new timeline, or "string," where none of your other trips happened, and if you screw something up, you can always make a new string where you didn't. However, it turns out that the strings can become tangled if there are too many of them, and making changes to history is like plucking the strings, causing them to "harmonize" with each other. If you get too many strings harmonizing, time itself will shatter from the vibrations. Jake nearly causes this to happen by saving JFK's life, but somehow he's able to save the world by making another string where that doesn't happen. All of this is explained by a hobo who's been driven insane by a very nasty version of Ripple Effect-Proof Memory (imagine remembering hundreds of different futures all at once, all in equal clarity) so there's a lot the reader never finds out.
- Poul Anderson:
- Time Patrol stories are historically well-researched and confusing as hell. Among other things, the future is "uptime" and the past is "downtime," which makes it sound counterintuitively like time is a river that flows uphill. (This is consistent with convention in geology and archeology, where an earlier period is "lower" because its evidence is in deeper strata.)
- Ditto in the 1632 series, the Grantville inhabitants from 2000 are "uptimers," the seventeenth century natives are "downtimers."
- The same terminology is used in The End of Eternity (by Asimov), where use words like "downwhen", "upwhen", "anywhen" and "everywhen".
- Animorphs made use of Time Travel occasionally, and each time it apparently worked differently. Different techniques of Time Travel were involved, at least one of which was by use of a thingy created by the closest thing to a God in the series, and another (a Bad Future-esque thing) was just flat-out never explained. The bad future was apparently a dream caused by an advanced being for some reason. Maybe.
- Eoin Colfer's Artemis Fowl and the Time Paradox does not actually feature any paradoxes. The prequel on the other hand... Specifically, an island was magically removed from normal time for 10,000 years, but the magic is breaking up and time starts running alternately forward and backward at varying speeds. Holly dies, but Artemis fires a shot backwards in time thus killing the demon who killed her and bringing her back to life. Furthermore, Artemis goes back in time and causes a mosaic of himself to be created hundreds of years in the past, a fact which is only noticed in the present day after he gets back. Artemis questions the first paradox, but eventually gives up trying to figure it out.
- In Last Guardian Opal defies Stable Time Loop by having her past self from Time Paradox killed, and manages to survive. What Opal's timeline looks like now is anyone's guess.
- The Book of All Hours duology by Hal Duncan doesn't even try to claim to be otherwise. It's such a mishmash of pocket universes, alternate universes, and paradox that causality can't even be seen with a telescope on a good day. Essentially: think of the universe as a huge piece of vellum on which reality has been written. Then crumple it up. Most characters make such a habit of going not just back and forth in time but sideways that one goes back to the day where he, as a child, met his elder self, and that elder self committed suicide... only now, as the elder self, shoots his younger self instead. Nothing happens to the elder.
- Date A Live has this thanks to the existence of Kurumi. A notable example occurs in the tenth and eleventh volumes. Origami (now a Spirit) has Kurumi send her back in time so that she can prevent her parents from being killed by a Spirit. Origami gets into a fight with another Spirit and one of her own stray attacks hits her parents' house. The revelation that she was the one responsible for her parents' deaths causes her to enter Inverse Form. She returns to the present (as Kurumi's power has a time limit) and causes massive destruction. Kurumi then sends Shido back in time in an attempt to prevent this. Shido initially fails but does comfort Origami after the fact, resulting in her obsessive love for him in the future. He then finds Kurumi's younger self and has her send him further back, allowing him to stop Origami from killing her parents. This creates a new timeline where Origami's parents still end up dying but in a traffic accident, so Origami no longer hates Spirits. However, she nevertheless inherits the power and personality of her original timeline's Inverse Form, which manifests as a split personality. Eventually, Origami's two personalities fuse into one, while the other Spirits also gain memories of the previous timeline.
- Terry Pratchett's Discworld novels:
- The History Monks are originally presented in Small Gods as ensuring everything happens the way it's supposed to (although, even then, the monk Lu-Tze decides to Screw Destiny).
- In Thief of Time, it's revealed that, following various alterations to the Disc's temporal dimensions, the "true history" barely exists, and their main job is to prevent the Timey-Wimey Ball from imploding.
- In Night Watch, when Vimes travels thirty years into the past to become his own mentor, even the monks aren't sure what's happening.
- If you try to place the times and events of some books, you will find they take place a couple years before a different book, and at the same time, hundreds of years before the IMMEDIATE SEQUEL of that different book.
- Sir Terry himself at one point explained that "There are no inconsistencies in the Discworld books; occasionally, however, there are alternate pasts."
- Dirk Gently's Holistic Detective Agency: Significant plot points hinge on characters being able to change the past (the villain wants to stop life evolving on Earth, and as part of the attempt to stop him, Dirk interrupts Coleridge when he's writing "Kublai Khan", the full text of which was previously established as existing in that universe). But the pay-off to the background gag of Richard's sofa hinges just as much on being a Stable Time Loop. This is during the same trip through time.
- Jack Chalker's Downtiming the Nightside: People leaping through time can affect changes. If the change is small enough, nothing much happens to the timeline, but significant changes can happen. Karl Marx is killed 3 different times, at 3 different points of his life. At the end of his life, not too significant. After he publishes Das Kapital, not too bad either. Before he publishes it on the other hand... And this is just the tip of the timey-wimey iceberg.
- The Dragonriders of Pern novels by Anne McCaffrey have time-travel courtesy of a side-effect of how the dragons teleport themselves and their riders all over the planet. However, you can't change the past. Several story lines, especially in the original novels to do with solving the empty weyrs, rely on the fact that major characters go back in time to make history happen, usually inadvertently. Meanwhile, coming close to yourself causes mental confusion. This happens to Lessa at least once and, of course, it drives the plot.
- Haruhi Suzumiya. The first thing we hear about time travel is that it's like a picture book; it looks continuous, but it's not, and scribbling on one page won't change the ending, so it's impossible to change the future. That gets thrown out the window pretty quick, with time loops up the wazoo. Several space-time locations get multiple time loops overlapping over them at the same time. However, starting in Novel 9, the timeline splits— not diverges, splits— and later fuses back together, and in novel 10 it is revealed that the evil time traveler Fujiwara is from a different future than Mikuru. In his, she's dead—and he wants to fix that, because she's his big sister. Unfortunately, in the timeline she's from (where she survived), her little brother never existed in the first place. So it's possible to change the future, right? Maybe. Because when all this craziness is going on, Kyon brings up the picture book analogy again, and it's confirmed that that is how time travel works (though at the same time it's implied to be an incomplete explanation). The mechanics of time travel in The 'Verse are pretty much incoherent now.
- Robert A. Heinlein:
- Heinlein wrote a short story called By His Bootstraps, in which the protagonist exploits a time machine to move himself forward in time. Simple enough. The Mind Screw comes in when he does this by his future self sending back his intermediate self to persuade his past self to enter the machine's portal. When the past self becomes the intermediate self, he attempts to double cross the future self, but that double cross naturally results in him becoming the future self. Follow all that?
- For a real, double whammy version of mind screw, read —All You Zombies— which chronicles a young man (later revealed to be post-real-sex change) taken back in time and tricked into impregnating his younger, female self (before s/he underwent said sex change); then he turns out to be the offspring of that union (time-relocated yet again), with the paradoxical result that he is both his own mother and father. As the story unfolds, all the major characters — the young single mother, her seducer, the alcoholic writer, the bartender who recruits him into the time-travel corps, and even the baby — are revealed to be the same person, at different stages of her/his life. How's your mind doing now?
- In Johnny and the Bomb, Pratchett explains that most time travellers forget the original timeline when they return to the new one because of the human tendency to accept what's around them as normal; but if you really try (or are reminded of it by some useful clue) you can remember how things used to be.
- Dean Koontz averted some time travel issues in Lightning by virtue of having the Nazis invent time travel, the limitation being that it can only send you forward (and then you snap back to your point of origin when you make the return trip). While this has its own problems, it at least eliminates the ability to murder your mother before she gave birth to you. You cannot change your own past, but you can change the past of anyone born after you so long as the changes you try to make are not contradictory, and you can bring objects back. Played straight in that if a contradiction is demanded, the portal will refuse the forward transfer (this gets the heroine killed in one timeline). "Destiny struggles to reassert the pattern that was meant to be." Sometimes happily, and sometimes not so happily, it succeeds.
- David Gerrold's The Man Who Folded Himself features a time-travel belt, which has the traveller completely paranoid about the possibility of a Temporal Paradox destroying him. It turns out that Temporal Paradoxes are impossible; Time Travel rewrites history except for the guy who travelled through time. Various Mind Screw moments: the protagonist has orgies with himself of different ages, writes himself out of history, has a family with himself as a female, eventually has that written out of history (but his son still exists) and culminates in finally giving himself (as the son, so he's his own father) the time travel device. On the last, the idea of where it came from is explored a couple of times and eventually it's hit upon that it's impossible to know where it came from, the creators must have been written out of history. Oh, and he kills Jesus at an early age. It's okay, he goes back and stops himself after finding out how much it screws with history.
- The Never Again series starts out simple enough. It seems to follow the many-worlds interpretation of quantum mechanics so that time travelers can do anything they want, but will create a new timeline that never intersects with the old. Then comes the third book, where that is thrown out the window, and the author's attempts to explain what is happening (with a lot of Technobabble about "intersecting universes" and the like) just raises further questions.
- The character of Phanthro in Relativity is a time-traveller from the distant future. He's constantly altering history (for the fun of it). When he's asked how he can alter the past without wiping his own time period out of existence, he just says, "Time doesn't work that way." No further explanation is ever given.
- Harry Harrison's The Stainless Steel Rat Saves the World features two overlapping timelines (one of which only has a temporary existence) and a loop. The lead character travels back in time to stop the Special Corps being removed from history, and manages to disrupt the enemy's plan. He then follows them further back in time, landing in an alternate history where Napoleon conquered Britain. He messes up the controls on the enemy time machine, and (after being rescued shortly before the alternate history disappears) follows them forward (but still long before his own time). He finds the villains (after a long time for them — so long they've forgotten everything except that he's the Enemy), but is unable to stop them; they travel back in time, and he's only saved by a time machine — allowing him to return to his own time — which he then sends back with the instructions for what he just did. Finally, he's told not to worry that he didn't stop the villains; they've just travelled to the first place he met them, where they will then travel back and create an alternate history where Napoleon conquered Britain, before...
- Star Trek: The novel Q-Squared introduces several alternate realities, including one based on the Bad Future in Yesterday's Enterprise. However, in this case, when the Ent-D finds the Ent-C, all the crew aboard it are already dead. Afraid of Klingons getting their hands on a Federation warship (even an old one), they scuttle it and move on. Oh, and by the end of the novel, that reality is even worse off, since its Picard and Riker are dead.
- In A Tale of Time City by Diana Wynne Jones, the titular city exists outside of the flow of history on the rest of the world. From this vantage point, the citizens see that history works like weather patterns — it shifts back and forth with minute details thanks to the butterfly effect and time loops. Basically, a more detailed explanation of the Timey-Wimey Ball, where shifts in the time travel theories are explained away as the changing "weather patterns" of time. For instance, on one day in Time City the inhabitants may observe that World War II begins in 1939, but on another day they may notice that it has changed to 1938. Perhaps time in the book is two-dimensional, with Time City time orthogonal to time everywhere else. Except it turns out that the history of Time City can shift back and forth too...
- In Jasper Fforde's Thursday Next novels, not only do the rules of Time Travel make no sense whatsoever, the main character (whose father is a time-traveller) realises this, and often lampshades it. In one book, the rules actually seem to change over the course of a conversation with her dad, but she realizes there's no point in even asking.
- In First Among Sequels, there is a subplot revolving around the fact that the time-travellers have mapped almost the entire future and found that Time Travel has not yet been invented. By the end of the book, Thursday and co. have managed to ensure that Time Travel is never invented, and thus, could never have been used earlier in the series. This means that several events from the previous four books including the plays of William Shakespeare and the beginning of all life on earth logically could not have happened. Since many of these events were the results of Stable Time Loops anyway, this is a case of Ascended Time Paradox. Or Mind Screw turned Up to Eleven. Either way, it's probably best just to apply the MST3K Mantra and enjoy the series.
- A significant part of the plot of The Woman Who Died a Lot is that the non-existence of time travel in a world where many people know they used to work for the ChronoGuard has actually made the Timey-Wimey Ball worse.
- In We Can't Rewind, the narrator makes several attempts to make sense of how his world's peculiar form of time travel works for the readers, and then gives up, explaining that he'll probably lose his mind if he keeps this up for much longer. He mentions that the temporal theorists of Merciar, from which he's writing this account, are doing no better at settling their controversies over how exactly inter-dimensional time travel works, and that most of Merciar's citizens have already given up trying to make sense of it in order to preserve their sanity and advised everyone else to do the same.
- In Connie Willis's stories, the time machine sends you not to your target time-and-place but to the nearest point such that your actions will not change history. (This is consistent with James Hogan's theory mentioned above, though the mechanism is not explicitly stated.) In Doomsday Book (which shared the Hugo Award in 1993), a history student aiming for England 1328 lands instead in 1348, where she can't affect history because everyone she meets will shortly be dead of the Plague.
- World of Warcraft: The novel trilogy War of the Ancients. Despite some dramatic changes (such as saving an entire race that originally went extinct), it's apparently okay to mess with time as long as the end result is roughly the same. Of course, it also helps explaining why said race appears rather plentiful in World of Warcraft after having been said to be extinct in an earlier novel...
- René Barjavel's novel Future Times Three is one of the first books to describe the Grandfather Paradox, and contains an appendix describing how the victim of the paradox is constantly oscillating between existence and non-existence. But there is also the case of an old servant who was saved from death by her bosses through time travel, who the hero does not remember having met because he visited the house before they went back in time to save her... and the servant seems to remember somehow that she should have died. Also, characters living during a war where common necessities are scarce are using Mental Time Travel to go back in time before the war to buy any supply they run out of in the present (which should mean that at one point in the past their cupboards must have been bursting with supplies).
- One episode of Mission To Zyxx involves a consultation with a being with centuries of perfect memory. It demonstrates that it can re-experience memories, and also draw other beings into those memories, and alter those memories, and leave people behind in those memories, and that people left behind in those memories will forget their own pasts to assimilate into the new timeline, and sometimes that means people in the old timeline have their memories changed and sometimes they don't... AJ gets repeated nosebleeds trying to keep up and the post-credits outtake is the actors getting confused during their own production.
- Dungeons & Dragons and Pathfinder organised play campaigns (Living Greyhawk, Pathfinder Society, Adventurers' League) feature interconnected modules which do not necessarily have to be played in order. This is often invoked to explain how a player character can have played in a later module before an earlier one.
- Feng Shui uses this trope quite effectively: The heroes can jump between 4 points in history by using the Netherworld. Transferring control of enough Feng Shui sites changes the future completely, except for anyone who's visited the Netherworld.
- Warhammer 40,000:
- This is a fundamental quality of Warp travel given that the flow of time relative to realspace changes randomly during transit. Navigation for The Imperium of Mankind requires the use of psychic Navigators to essentially feel their way to their destination, avoiding the worst of the warp storms and riding favourable currents to reach their destination. However, given the abovementioned mutability of time along the way, when you arrive is anyone's guess. The crew could be in transit for weeks or months at a time to arrive at their destination at the same time as when they left, centuries late, or even before they set out, if you even get there at all. A graphical history for a given ship would more closely resemble a circuit diagram than a timeline if plotted out.
- One specific example had an Ork leader accidentally end up at his starting location just before the fleet left, and then promptly attacked and killed his past self to get a spare of his favorite gun (the Waaagh! disbanded in the ensuing confusion).
- There is also a long-running war between Eldar Farseers (who can manipulate current events to change the future) and actual time travelers from the Necron dynasties and Imperial Inquisition (who may or may not have accidentally erased themselves from the timeline).
- One Imperial ship responded to a distress signal, but was ambushed in the Warp. Just before its destruction it managed to send out a distress signal...
- Apollo Justice: Ace Attorney manages the difficult trick of pulling this off in a game that doesn't feature time travel. In the last episode, Phoenix's investigation as shown would not be possible unless he could actually travel through time, rather than being able to select different times just being a tool for the convenience of the jury. He uses evidence he gathers in the present in the past, as well as evidence he gathers later in the same portion of the timeline in earlier incidents. Justified in that the investigation you see is a simulated version being played out by the jury.
- Time Hollow suffers from this trope at times. At one point, you rescue a mother and son from dying in a bus crash. Immediately afterwards, time refuses to change. So you try again. And again, nothing happens. Turns out the mother deliberately RE-changed events to cause her and her son's death. This is handwaved with an explanation that objects and people pulled or otherwise sent through a time warp become 'detached' in time. It may make your head hurt a bit more when you are able to talk to the mother, older, in the timeline in which you saved her, even though that timeline, from your perspective, DOES NOT EXIST because she keeps changing the past to prevent it.
- Virtue's Last Reward requires Sigma to betray Phi at a critical juncture in order to open a plot lock. Due to this being an incredibly ridiculous and out-of-character thing to do, it is highly likely the player will only try it after Phi betrays Sigma in the alternate branch where Sigma allied — which she explicitly declares she's doing only because of Sigma's betrayal in the other path. You could almost call this a Stable Time Loop, except that it's an interaction between two different alternate universes that can only connect through Phi and Sigma's Time Travel powers.
- This is also a possible explanation for Seven's Easy Amnesia in Nine Hours, Nine Persons, Nine Doors — because his past knowledge is in flux due to Akane's survival hinging on the outcome of his current situation, he can't remember things clearly until after the situation resolves.
- Red vs. Blue starts out with a Stable Time Loop when Church keeps going back in time and ends up causing almost every problem that happened to the Blue Team. Then in season five, Wyoming uses his time travel ability (which Church was originally using without knowing it) to try and win the battle. Tucker has Ripple Effect-Proof Memory thanks to his sword and they end up doing things, and then undoing them. For example, Caboose is killed by the tank, and Tex gets knocked out/killed by Wyoming. In the "final draft" of the timeline, Tucker yells at Caboose to stay away, and warns Tex that Wyoming knows that she's there. Then it turns back into Stable Time Loop when Caboose's mental image of Sister, who is a guy, gets pulled into the real world. S/he ends up materializing next to a dead Wyoming, whose suit malfunctions, sending him all the way back to Sidewinder. Turns out, he was the mysterious "Yellow Church" that fans speculated about for years.
- Since the "Yellow Church" claimed his plan to solve the Sidewinder crisis "seemed like such a good idea at the time", it could be safe to speculate Sister/Yellow Church is there due to a further loop leading back to Sidewinder.
- The series later attempts to explain all this earlier time-travel nonsense during the "Recollections" trilogy of seasons by explaining that the Red and Blue soldiers are actually simulation troopers meant to test Freelancer troops against a myriad of mad situations and everything they were subjected to in Blood Gulch was in fact a controlled situation they weren't meant to understand.
- Actually Word of God from Burnie Burns has confirmed that Church going back in time repeatedly never really happened, and was merely Gamma and Omega trying to cause Alpha to fracture into more A.I. fragments. Nobody moved through time in Season 3. Yes this is a major retcon, but as of Season 8 it is considered the canonical explanation.
- Lampshaded in Sonic for Hire at the start of Season 6. As Sonic announces he would travel through time to make himself famous again, Tails points out the amount of inconsistent Plot Holes that would occur from this. With some of the characters being unaffected by the time effects, randomly having alterations on their bodies, or the universe falling apart.
- Used to great effect in The 10 Doctors. It's even mentioned by name as to how all ten Doctors can be in one place at the same time.
Third Doctor: You see... time is... well... it's...
Second Doctor: Well, it's... It's not linear... It is more sort of...
Tenth Doctor: It's... squishy-squashy...
Seventh Doctor: Wibbly wobbly.
Sixth Doctor: Semi-fluid!
Fifth Doctor: Gelatinous.
Ninth Doctor: Mushy-gooey.
Drax: Higgledy piggledy.
Fourth Doctor: Hi-ho the dairy-o!
Romana II: Green grow the rushes-o!
First Doctor: Alright, you lot!
- Awful Hospital: The alien zones don't always use "time" as we humans understand it, but something called "layers." Chronology can sometimes jump around on its own, via layers, without Fern needing to enter a time machine:
Staph: As you read this letter, our kingdom will have undergone many generations of development... at least from our perception. Don't fret! In your own perception sphere, we are very much alive, and I'm certain you will have an opportunity to drop in and say 'hello.' Does that make sense? Sorry, we still don't really have a handle on how you experience the layers.
- In Bob and George most of the characters can never find out what kind of rule Time Travel goes by, and one person once said it can be changed by the setting on the time machine. However, it appears that they follow Stable Time Loop rules, as no time period is ever affected by what happens in another. Indeed, the only way time travel is different than going to a different dimension is that people think it may change history.
- Dr. Light's lab is clearly shown being pre-destroyed by a time ripple tearing through it and enforcing events from the new past. So yes, the past can be changed if you use the time machine right.
- The ending however, suggest a stable time-loop, as it ends with a suggestion from a time-travelling ghost of Zero telling Wily to not activate him so he won't kill everyone. Then they all fake their death and move to Acapulco to prevent a temporal paradox.
- There is a very good reason why "I hate Time Travel," is one of the more common Catch Phrases of the comic.
- At another point, Protoman adds a fresh level of murk due to a) lacking Ripple Effect-Proof Memory and b) being paranoid enough to know he lacks Ripple Effect-Proof Memory, by remarking that a time-travel story is exactly how he remembered the events in question...well, it's how he remembers it now.
- Dresden Codak: Dresden fucking Codak. This is what happens when Dada Comics undergo Cerebus Syndrome; leave your sanity at the door. The basic mechanics of the wimey-ball are pretty clearly laid out at the bottom of this page, though as always some inconsistencies appear if you think about it too much (somehow, the artificial wormhole doesn't split the timeline, but the natural one does).
- Earthsong has a bit of timey-wimey-ball action, since character are pulled together to one time, and then returned back to the moment they left after an indeterminate amount of time.
- The sequel fic Forever Janette intentionally invokes the Timey-Wimey Ball by subverting the show's use of San Dimas Time — by letting the Fifth Doctor meet the Master from the Seventh Doctor's time. It doesn't say how this is possible, other than a passing mention that the two Time Lords are "off-phase" from a common Gallifreyan synchronicity.
- Discussed in El Goonish Shive: Grace expresses confusion about how in Back to the Future Marty is affected by the Delayed Ripple Effect and while at the same time possessing Ripple Effect-Proof Memory. Justin tells her that the sequels don't make sense of this inconsistency and further that time travel is not allowed to make sense.
- This page of the Midnight Crew intermission in Homestuck typifies the response. Though most of the time travel shenanigans seem fairly self-consistent, it's still hella complex.
- In the main continuity of the series, it gets worse when Future!Dave starts incorporating Time Travel shenanigans. And even he doesn't understand all the mechanisms behind it, his advice to the other characters (and the audience) is just basically "Don't overthink it."
Dave: see the thing with time travel is
Dave: you cant overthink it
Dave: you just got to roll with it and see what happens
Dave: and above all try not to do anything retarded
John: i'm just the timey-wimey messenger here.
- However, Magic A Is Magic A applies heavily and every form of time travel is internally consistent. The problem arises when there are at least four different forms of time travel, and possibly even more, all of which abide different rules
- Heroes of Time have two options. Either A) They change destiny and cause a branch timeline, or B) You Already Changed the Past. They naturally have some intuition about what changes cause what. Time magic practiced by the Felt is more loose, and can be used for pretty much any form of Time Travel. And then there's the weird stuff, like the Furthest Ring distorting space and time, potentially causing someone to meet their past selves by traveling in a straight line and Skaian portals.
- The Doctor's Trope-Naming soundbite is used in "Arisen Anew" from the Alternia Bound album.
- All the rules get thrown out the window when John touches a strange artifact that makes him unstuck from reality. He has the power to make real and permanent changes in the alpha timeline.
- In the main continuity of the series, it gets worse when Future!Dave starts incorporating Time Travel shenanigans. And even he doesn't understand all the mechanisms behind it, his advice to the other characters (and the audience) is just basically "Don't overthink it."
- Iji Reborn: Averted. The Iji that joins present Iji and Verde is not a past version of the present Iji, it is the Iji of Iji.
- Time travel in Irregular Webcomic! at first appears to work in a Stable Time Loop fashion, but then it's revealed that It's possible to "break" a Stable Time Loop, an action capable of destroying the entire universe. Several time loops have already been broken. And now Every universe, save the "espionage" theme universe, has been destroyed. They got better. And now apparently the timeline is too broken to go back pre-1933 (specifically the date of the Reichstag Fire). Complete with a link to this very article.
- Looking for Group has a big fat temporal loop in the Kethenecia arc in Book 3, but really the arc underlies the whole story so far. It's still uncertain if the protagonists can actually change the timeline should they chose to, since so far they did their best to fulfill the prophecies.
- It's openly stated by a member of the Time Police in L's Empire that all bets are off if you time travel via magic.
- Manly Guys Doing Manly Things heavily lampshades this trope. The main requirement to avoid the variety of paradoxes is "Don't think about time travel".
- The characters of Melonpool handled time travel pretty responsibly the first two times. After they disable a mechanism that forbade them from being able to interact with things they had already done, including their past selves who were the time travelers, the whole affair became a convoluted mess and every new revelation had to be resolved by going back in time to stop themselves from changing what happened by going back in time to stop themselves from changing what happened. The moral of the story is: don't mess with time travel or your universe will implode.
- Trying to track the timeline changes in Misfile may lead to you repeating this trope name over and over and over again.
- An extended time-travel subplot establishes that it is difficult, but not impossible, to change your own history. Physical time-travel takes all the energy that exists in the Universe or, as it turns out, in some other universe that's just out of luck, but it's possible to transfer your consciousness back or forward in time into your own body, and you can undergo changes as a result of altered behavior. For instance, Dave never smoked. At several points, the question of paradoxes comes up, and it is immediately dismissed by pointing out that thinking about it could cause it to happen, so it's better not to.
- The same storyline provides an example of inconsistent time travel effects within a single sub-plot. Dave didn't cease to have ever smoked until after the time travel; however, Caliban's demotion, though also caused by the time travel, was established backstory before the time travel occurred.
- There don't seem to be any concrete rules to Sluggy Freelance Time Travel. Possibly justified by the presence of beings like Father Time, Uncle Time, and the Fate Spiders who have an interest in making sure time runs smoothly and/or in a fun way.
- The fact that the original fate spider gives up, quits his job and then only comes back after his successor has screwed everything up even more says a lot, at this point they seem to pretty much just watch and be amazed that all of creation hasn't gone up in flames already.
- In a later strip, Old-Riff says that Time Travel follows the branching timeline rules, and therefore you can't change the past, you're just abandoning the Bad Future in favor of a different universe. But really, the way it works, this revelation doesn't actually contradict anything, since from the characters' perspective, they would have no way of knowing.
- K'Z'K eventually explains the exact details here. If you travel back to the past and make changes, Khronus's Web of Fate will use probability manipulation to try to shift things back on course and create a Stable Time Loop, overwriting the original timeline with minor tweaks. If you manage to change things beyond the Fate Web's ability to create a Stable Time Loop, the altered timeline will split into an Alternate Universe. Under certain circumstances, the Fate Web's safety mechanisms can fail, which will cause a Time Crash, destroying the universe.
- This is probably gonna be the only way to understand the whole time traveling bit in Sonichu. To wit, Author Avatar Chris is launched into the future where he is able to help those in the future make the vaccine for homosexuality (even if that's not how it works) before being able to convince his future wife Lovely Weather he is his future self (despite the fact that he'd be ten or so years older) and do the nasty. He comes back, gives Magi-Chan Sonichu a Sonichu Ball and tells him to go back and get some of the vaccine to bring back to the past so they can cure everyone years earlier. And while he does talk to the past version of Lovely Weather, there's the case of the vaccine — if he brought the vaccine back from the past to cure everyone, why would there be a need for it in the future and oh, going cross-eyed.
- The Starship Destiny:
- The robot Gizmo goes back in time to kill Hitler, reasoning that he can then go back again and stop himself. Instead, his first iteration convinces him to join in, since he can just go back again, and stop himself. Predictably, they end up having dozens of Gizmos brutalizing Hitler before he's had enough and stops his first self... and gives him a video recording of the event.
- In another chapter, Gizmo went insane from a virus while saving the ship. The other crew members fix this by taking his head off (it contains his processors and memory drives), going back in time to just before he went insane, and switching heads, thus bringing his sane head back to the present while the insane one faces the virus (presumably, he can't go even insaner).
- Done hilariously badly in the abandoned indie RPG Zybourne Clock:
Imagine four balls on the edge of a cliff. Say a direct copy of the ball nearest the cliff is sent to the back of the line of balls and takes the place of the first ball. The formerly first ball becomes the second, the second becomes the third, and the fourth falls off the cliff. Time works the same way.
- Doctor Whooves Adventures, being a Doctor Who fanfiction, have a tendency. Traveler in particular.
- According to Huey in Ducktalez 5, the time-travelling Deweys all come from alternate timelines that are created when one of them tries to change history. Huey offers a situation, but that fails. Also, Dewey tries to ask for the Doctor's help, but that fails.
- Mind My Gap is a plot made of this. It seem at one point that up to four chronologically separate events with the same characters involved are happening at exactly the same time
- Phaeton has time travel mechanics, but also has laws, and etiquette, all to prevent this from happening. Still there are people who don't follow the "Six Minute Flux" mechanic and cause this.
- The Terminator variety is spoofed in the Atop the Fourth Wall, where time travel doesn't work on pants.
- Adventure Time: In "Is That You?", Jake and Finn ends up helping Prismo (who was seemingly Killed Off for Real in "Wake Up") with a plan that involves using a convoluted series of time loops and paradoxes to replace Prismo's original host with an alternate version of Jake. At one point Finn hangs a lampshade when he points out the whole plan "seems rickety as yoga balls".
- In the double-episode "Two Futures" of Captain Planet and the Planeteers, Wheeler uses a time pool to go back and prevent himself from receiving the fire ring. This results in a crapsack future because the Planeteers never became a team and saved the environment (though why they didn't just find another guy to accept it is never explained). He then goes back and prevents himself from preventing himself from getting the ring. Then they both escape into the time pool again and merge for some reason. To make sure the viewers knew things were restored to normal, a scene from the utopian future is shown at the very end.
- Time travel in The Fairly OddParents is... confusing. The first time Time Travel is used as a plot device, and in most subsequent appearances, history is very malleable and can easily be changed... with serious consequences.
- However, the episode "The Secret Origin of Denzel Crocker" appears to utilize a straight Stable Time Loop... however Timmy's time traveling, in addition to causing Crocker to lose his fairies as a kid, also gave him a much more sophisticated fairy-tracker which he didn't originally have as an adult, meaning that Crocker must have lost his fairies a slightly different way the "first time around".
- In a much later episode when Timmy wishes he were never born, a la It's a Wonderful Life, Jorgen reveals that Crocker's childhood would never have been ruined had Timmy never existed, which means that there was no "first time around" note . In other words, the writers wanted to use both Stable Time Loops and Temporal Paradoxes at the same time, resulting in a confusing mess. Cosmo did a lot to get little Crocker obsessed with fairies, but he only got the opportunity due to Timmy.
- Time travel results in the creation of Stable Time Loops... except when it doesn't. In "Roswell That Ends Well", You Already Changed the Past is in effect, and everything makes sense. Then "The Why of Fry" contradicts this, and Fry succeeds in altering his own past (he doesn't prevent himself from getting cryogenically frozen, as he originally intended, but he does convince the Nibblonians to give him a better getaway scooter). Then, Bender's Big Score throws sense out the window: Bender's rampant time travel is revealed as the cause of some events from previous episodes (such as the fossilization of Seymour, and the first destruction of Old New York by flying saucers), while completely altering some other events (the final scene of "Jurassic Bark" gets retconned). Both stable time loops (like the tattoo on Fry's butt) and utter nonsense (like Hermes Conrad stealing his own body from the past) work equally well. Rather appropriately, Bender's time travel is carried out by a literal Timey-Wimey Ball.
- The entire existence of Lars Fillmore is built on a combination of a Stable Time Loop and an Alternate Timeline. In the future, Fry meets Lars before going back to his own time. He then takes another trip back in time by an hour, displacing the Fry that existed at that time and turning him into a "time-paradox duplicate." The duplicate eventually becomes Lars, following his other self to the future and inspiring the original Fry to take on the false identity of Lars once he becomes a duplicate though his upcoming use of time travel.
- Then there's Professor Farnsworth's time machine in "The Late Philip J. Fry", which could only go forward in time. When Farnsworth, Fry and Bender returned to a new, identical universe (making the Big Bounce theory true), it's impossible to know if the killing of the fish or Hitler did anything to Universe Two because they didn't get to stop in the 31st century to find out. They had to go around again to finally make a stop at Universe 3. This leads to all sorts of crazy implications as to what happened to the time traveling crew in the 2nd universe...do they kill their Universe 4 selves?
- On the DVD commentary for "Roswell", the writers say that they initially intended to avoid doing any time travel stories, because it's basically impossible to make them make sense, but eventually they couldn't resist.
- "You mustn't interfere with the past. Don't do anything that affects anything, unless it turns out you were supposed to do it. In which case, for the love of God, don't not do it!"
- Milo Murphy's Law has characters change the past through time travel frequently, yet also has a number of gags that rely on the assumption of a Stable Time Loop. It's also inconsistent about when characters can or can't remember events that got erased from the timeline.
- The Penguins of Madagascar has Kowalski try to stop two paradoxes that he created at the same time. While it's eventually resolved with a stable time loop, the second/third Kowalski couldn't have existed without having it's own paradox. It's... confusing. And the paradoxes effect time is only a few hours.
- The plot of a Pinky and the Brain episode, in which the mice try to obtain a "World Domination Kit" from the future. It doesn't even try to make sense, but suffice to say it ended with the lab full of hundreds of Pinkys and Brains, and the ending tune changed to "They're Pinkys, they're Pinkys and the Brain Brain Brain Brain Brain Brain Brain Brain Brain Brain."
- Randy Cunningham: 9th Grade Ninja: When the past was altered so the Sorcerer's imprisonment never happened, it got the Sorcerer free but didn't change the world in any way that reflected the damages he would have caused during eight centuries of altered history. No explanations were given.
- Rick and Morty: In "Rattlestar Ricklactica", Morty accidentally gives a species of racist alien snakes the secrets of the universe, causing them to band together to invent Time Travel to travel across space and time to kill Morty. Rick solves the issue by going back himself and inventing time travel for the snakes at an earlier point in their species' history. Things rapidly get out of hand because the snakes cannot decide what events should and shouldn't happen; the palace of Snake Hitler becomes a chaotic battleground of dozens of time travellers trying to either kill or save him. Eventually the Time Police have to get involved and erase the species from existence.
- In the finale of Samurai Jack, Ashi uses her powers as Aku's daughter to open a portal in time which sends her and Jack back in time to the point where Jack was sent to the future. Jack drops out just after Aku flung his past selt into the future to begin with, and then kills Aku. Ashi hangs on for a weirdly long time after that (apparently at least a few weeks) before she collapses, having just enough time to explain that, because she was born of Aku way in the future, killing him in the past meant she was never born, before she faded from existence. Which raises the question: With Aku already dead, and therefore Ashi having never existed, who the hell is in the future to send Jack back in time to kill Aku?
- Sealab 2021: "Lost In Time" shows Stormy and Quinn trying to steal cable for Captain Murphy and inadvertently cause a rift that sends them back in time to just before they left Sealab (about 15 minutes). They try to prevent themselves from causing the rift, but past Captain Murphy is convinced they are evil dopplegangers and not time travelers, so he has them locked in the brig. When their past-selves cause the rift (again), they experience the same events but somehow the original pair is also in the brig when they get there. So now there's 3 Stormies and 3 Quinns running around. Since the time difference is only 15 minutes, each successive Stormy and Quinn react in the same way, and since each pair is unable to stop the next pair, the number of Stormies and Quinns keeps growing until the brig is filled with them and they have to start referring to each other by which iteration of the loop they came from (i.e. Quinn 1, Quin 2, "the 7s", etc). Eventually time itself is getting so screwed up that weird alternate versions of them start showing up too (like pixie versions, or Quinn as Jabba the Hutt and Stormy as Salacious Crumb). The Quinns band together to try and think of a solution, while the Stormies play dodgeball. Ultimately, one of the Stormies reveals that they've been using their communicator watch(es) the whole time (but only with already locked up Stormies). One of the Quinns borrows it to call the version who is out stealing cable and finally ends the loop by averting the next explosion. Then, instead of using the combined brain power of dozens of genius Quinns to solve major world problems, Captain Murphy has all the duplicates fight to the death in the gym for his amusement.
- Sonic the Hedgehog:
- Sonic the Hedgehog (SatAM) screws up its time travel rules quite confusingly. Sonic and Sally try to travel back in time to before Robotnik's coup in order to stop him, but soon discover that this is impossible and they can't change the past, merely act out or ensure predetermined events (Sonic causes Robotnik's arm to be robotized, saves his younger self from getting captured, etc.). However at the last moment Sally attempts to change the fate of her nanny by telling her future information and it works, even though it logically shouldn't have. Even more confusingly, Ripple Effect-Proof Memory is in effect, so Sonic and Sally don't remember interacting with someone they now logically should. Sonic is appropriately confused.
- In the Adventures of Sonic the Hedgehog multi-parter Scratch and Grounder made it so a couple of Sonic's ancestors didn't meet, making Sonic disappear. But for some reason Tails is still there and able to fix this.
- South Park:
- In one episode, Cartman freezes himself and is thawed out 500 years in the future. He then makes repeated calls to Kyle via a phone that reaches back through time, which makes changes to his time. He and everyone else 500 years from now only know the world the way it is after the changes. However, when he makes one more change at the end that hugely impacts history, he only remembers what the world was like before the change, while from everyone else's point of view it's always been that way.
- In the episode "Goobacks" immigrants from the future come back through a time portal to get jobs in the present. When the townspeople try to improve the future so the immigrants will stay in their time period, the immigrants begin to fade away. A reporter notes that scientists say the time border follows Terminator rules meaning it's one way only and you can't go back as opposed to Back to the Future rules, where back and forth is possible, and Timerider rules, which are just plain silly.
- Static Shock has a one-shot time-traveling metahuman who briefly teams up with Static and Gear, only to decide her powers are too dangerous, go back in time to before the Big Bang, and steal her past self's bicycle so she couldn't get caught up in it. Would be a classic paradox were it not for the fact that Static and Gear still remember the previous version of what happened. Upon pointing this out, Gear comments that if you try too hard to figure it out, your head will explode.
- Teen Titans: "How Long is Forever?" deals with a supervillain named Warp from 100 years in the future who steals a device, which he knows he'll get away with because there's a Stable Time Loop and history books say it gets stolen on the night he returned to. In the fight, Starfire ends up flung 20 years into a Bad Future where the Titans have fallen apart without her. By the end of the episode, she manages to return to the present and saves the device, proving Warp wrong. If there's no stable time loop, why do the history books already claim Warp steals the device? Also, how can Starfire end up in a future where she disappeared while that same future results in her returning to the present, negating its own existence?
- This episode of Tek Jansen, a series of shorts originally created for Stephen Colbert's show, illustrates how bad (or awesome) this trope can get.
- A short summary for all the non-Americans who can't see the video: The Prince and his three attendants, one of whom is named Schlorb, crash land on a planet. Tek Jansen arrives (and to clarify arrives means appear out of nowhere with a time machine) from the future to protect them. Then a second Tek Jansen arrives from further in the future and shoots the first Tek Jansen. Tek explains that in five minutes the first Tek would have eaten a couple of berserker berries, gone insane, and attacked them. He then eats the berries and goes insane. A third Tek Jansen arrives from sometime and shoots the second Tek. He says that Schlorb explained everything to him, but does not remember when. A fourth Tek arrives from the future and sends the third Tek into the past because Schlorb has an important message for him. A fifth Tek accidentally arrives naked with some lady on top of a console. The fourth Tek leaves (and to clarify leaves means disappear with the time machine) with them. A sixth Tek walks on screen with two clean shirts and does not recognize the Prince or his attendants. A seventh Tek arrives and shoots the sixth Tek because one of the shirts had too much starch in it. The seventh Tek is then eaten by a slime monster. An eighth Tek arrives in some sort of armor and asks if he was eaten by the slime monster yet. The kids say yes and Tek leaves frustrated. A ninth Tek arrives and says that he is pretty sure that he needs to take Schlorb into the past, and proceeds to do so. A battered tenth Tek arrives and warns the kids to stay out of caves, then leaves. An eleventh Tek arrives and says he knows of a great cave that they can camp out in. A twelfth Tek arrives, shoot the eleventh Tek, hands the group an egg beater, tells them to hand it to the next Tek that appears, and leaves. The Prince points out that this is pretty fucked up. A thirteenth Tek arrives fighting a giant egg. Tek grabs the egg beater and leaves, still fighting the egg. A fourteenth Tek arrives and explains that all this time travel has opened a chrono-rift in the space-time continuum. He is going to go fix it, but he wants the kids to do exactly what the next Tek tells them to. He leaves. But then a large group of Teks arrive all pointing in different direction. They proceed to fight each other, and the episode ends on a cliffhanger. This all happens in two minutes. You got all that?
- There's a gigantic lampshade in Tripping the Rift. The crew saves the day by turning back time Superham-style: by flying the ship around a star counterclockwise really fast. While they're setting up, they discuss the inconsistency of the rules of time travel and the problems with changing the past.
- In X-Men, Bishop keeps his memories of the previous chain of events when he returns into the future. Later the two parter "One Man's Worth" has the death of Charles Xavier before he founded X-Men resulting into a war-torn present. Wolverine and Storm from this changed reality travel into the past to help to save him. After the successful mission accomplishment they return into the future (present time) and for some reason lose all their memories about the Xavier-less reality.