Timey Wimey Ball / Live-Action Films

• 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.
• Looper:
  • 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 above include up to erasing a person from existence. Despite Old Joe never having existed, every event he caused and was a part of still occurred. Cid remains injured despite the fact the gunman who shot him never existed. Young Joe remains dead despite the fact that Old Joe being dead should cause a Time Paradox as the reason for his suicide never existed.
  • 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 Set Right What Once Went 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.
• 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.
• In 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.

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