History Main / TimeIsDangerous

* In the ''WesternAnimation/BatmanTheAnimatedSeries'' episode "Time Out of Joint", Clock King uses a time-altering device to trap Batman and Robin in a "bubble" of slowed time, where [[YearOutsideHourInside seconds for them pass as hours on the outside]]. Batman points out that objects "outside" the bubble are moving relatively at tens of thousands of miles an hour while they are comparatively "standing still". Meaning there will be an enormous (think asteroid impact or nuclear weapon) explosion if anything collides with them in their "frozen" state. Fortunately Batman defuses the trap before it can happen. FridgeLogic suggests that everybody outside the bubble just saw the Batmobile parked in the middle of the highway for a full day (or however long they were trapped), with the dynamic duo sitting nearly motionless inside. It's a good thing nobody tried to knock on the window to see if they were ok.

* In the ''WesternAnimation/JusticeLeague'' episode "The Once and Future Thing: Weird Western Tales", Chronos breaks into a storage locker on the Watchtower by locally speeding up time so that a section of the [[RapidAging door ages]] and disintegrates in a few seconds. This same villain then brings treasure of all kinds into one place, including the Pyramids, destabilizing time to the point that Wonder Woman is erased without him doing anything and John Stewart is replaced with Hal Jordan. [[spoiler: His fate at the end of the episode is to [[AndIMustScream permanently lock him]] in the [[GroundhogDayLoop ten seconds before he left]].]]
* The titular organization in ''[[WesternAnimation/MenInBlackTheSeries Men In Black: The Series]]'' has a complete ban on time travel devices from the supply of ImportedAlienPhlebotinum they periodically get. We see why when a conspiracy nut steals such a device to RetGone the entire organization, slowly unraveling it by disappearing its founders to a timeless void with everyone unawares to the timeline changes.

* In ''Manga/{{Doraemon}}'', TimeTravel is achieved by going through a tunnel-like space on your TimeMachine. Should one get knocked out of the machine and into the tunnel, one will be stranded in time. The problem is, Doraemon's time machine is basically just some futuristic devices bolted to a ''tatami'', so the risk of being thrown overboard is always there. Dorami's is safe, because it's a flower-shaped capsule. Have we mentioned that some bad guys have their own time machine, [[Series/PimpMyRide so you can have a chase in time while you chase in time?]]

** In ''VideoGame/EarthBound'', the Phase Distorter 3 destroys living things when it travels, requiring the party to have their minds uploaded into robotic bodies before they can use it.

* ''Series/SevenDays'': There are so many things wrong with the Sphere. First of all, while it's [[ExactlyWhatItSaysOnTheTin very accurate]] [[TimeAndRelativeDimensionsInSpace in time travel, landing it]] ''[[TimeAndRelativeDimensionsInSpace where]]'' [[TimeAndRelativeDimensionsInSpace you want to be]] requires precise piloting. Second, [[OurTimeTravelIsDifferent Our Time Travel Is]] '''''[[AgonyBeam really]]''' [[AgonyBeam painful]]''. Third, well, go to the page and check out the list of {{Phlebotinum Breakdown}}s the machine suffered. That's probably not even the full list!

* In ''LightNovel/TheZashikiWarashiOfIntellectualVillage'' Shinobu uses a time travel package that sends him ten years into the past. While he is protected by the package, if he tries to bring anything back to the present with him it will instantly experience the effects of ten years passing which would be fatal to any living being. [[spoiler:Youkai, having no need for food or water, can survive this. Shinobu exploits this so that the Aburatori can experience ten years without killing, fulfilling the conditions to transform him into a benevolent Kaeshigami]].

* ''Film/{{Tenet}}'' is chock-full of this trope, although it portrays "inversion", where an object's flow of time is reversed, rather than conventional time travel: The Protagonist is warned not to attempt an inversion unless he can see his future, inverted self following suit, inverted individuals cannot breathe uninverted air and require [[GasMaskMooks gas masks]] and airlocks to survive in the past, inverted explosives crush victims within walls, inverted fire sucks thermal energy out of its environment to flash-freeze victims, inverted bullets inflict a type of radiation poisoning, characters risk becoming trapped in an inverted state if they invert without access to a Turnstile somewhere in the past, [[spoiler:the Protagonist almost murders a future version of himself]] and the movie goes as far as to suggest inverted matter to be analogous to ''antimatter'', resulting in the instantaneous annihilation of any particle that comes into contact with its inverted self. Throughout the film the characters are constantly fighting against strategic applications of inversion, such as "Dead Drops" (nigh-untraceable time capsules between present and future) or "Posterity" (scanning for electronic records in the future to anticipate actions in the present). "Bitemporal" warfare is also [[WarIsHell generally hell]], as any counterespionage is impossible and any action undertaken to defeat an inverted antagonist would have already happened from their point of view. Taken UpToEleven in the finale with [[spoiler:[[{{Macguffin}} The Algorithm]], a schematic for a superweapon capable of inverting the entire planet to [[OmnicidalManiac completely erase the present from history]] and allowing the future to RestartTheWorld.]]

* In Marvel, [[ComicBook/AllNewXMen a series of]] [[Comicbook/AgeOfUltron time travel disasters]] has caused a TimeCrash that has snapped RubberBandHistory. This means any time traveller can permanently change history of the mainstream universe without worrying about causality. [[ComicBook/IncredibleHulk The Hulk]] is tasked with going through time to fix it since a normal man whose suit failed ended up with [[BodyHorror different parts of his body aged to different years ranging from 90 to 2 weeks old]].

* In ''[[https://forums.sufficientvelocity.com/threads/hybrid-hive-eat-shard-worm-mgln.55056/ Hybrid Hive: Eat Shard?]]'', Taylor and Hive are experimenting with a power/spell hybrid they believe will cause time travel. To be safe, they perform the experiment on an alternate version of Mars. ''Something'' happens and they realize that the Mars they were using now [[RetGone never existed]]. Taylor and Hive both agree to put that on the "don't use this" list. The author has implied that the ''universe itself'' did this, and it was only being in a separate dimension that protected the two of them.

* In ''The Time Ships'', the time traveling jeep was blown to pieces by intersection with a reverse growing tree while they were traveling backwards with expiring fuel. Lucky, the time travelers survived.

* In the short-short story "The Man from When" by Danny Plachta a time-traveller arrives from the future and states that his departure caused such an expenditure of energy that it completely wiped out the Earth of his time. He then reveals that [[spoiler: he has travelled back all of ''eighteen minutes''.]]

* In ''Strange Attractors'' by Creator/WilliamSleator, the creation of a CrapsackWorld AlternateUniverse is almost the only outcome that could come of sending anything (much less a person) into the past.

* ''VideoGame/NeoTheWorldEndsWithYou'': Rindo has the ability to, in dire situations, move the timeline forward and backward to make different decisions and change the future. [[spoiler:Except the souls of the old timeline linger and convert into entities that can eventually grow numerous and powerful enough to erase an entire city from existence and everyone's memories. This ends up being the basis of the BigBad's plan. On top of that, attempting to absorb said entities can strengthen you at the cost of making you BrainwashedAndCrazy.]]

* In the 2006 film ''Film/DejaVu'', [[spoiler: passing through a window into the past is possible, but exceedingly dangerous to living beings.]] Special Agent Carlin plans for this by [[spoiler: teleporting himself into an ER with instructions to resuscitate him.]]

However, not all time machines are like that. Some could get downright dangerous to use, because trivial mistakes at any point during time machine operation could get time travelers dead. Worse, the world or more could get destroyed by the time machine itself. There can be many reasons on why the time machine itself is dangerous. What if the time machine [[TeleFrag overlaps matter]] on its arrival? What if what powers the time machine itself is dangerous, due to various reasons from radioactivity, instability, or just sheer amounts of power necessary? Or, what if some of the time machine's physics requirements are dangerous? Or what if the time traveler is likely to end up [[TimeAndRelativeDimensionsInSpace someplace unsafe]], like anywhere but the surface of the earth?

* In the ''WesternAnimation/JusticeLeague'' episode "The Once and Future Thing: Weird Western Tales", Chronos breaks into a storage locker on the Watchtower by locally speeding up time so that a section of the door ages and disintegrates in a few seconds.

** The first book has ComicBook/DoctorStrange's mastery of temporal manipulation, thanks to natural talent as a TimeMaster and a {{Seer}} being magnified by [[spoiler: exposure to the Time Stone - which also made him TheAgeless -]], as ''the'' key part of what makes him so incredibly dangerous: it allows him to gather vast amounts of knowledge, which allows him to mastermind the grand-scale manipulation of the series' colossal GambitPileUp, manipulating characters from ordinary teenagers to the Endless themselves. It gets to the point where the combat related abilities, such as his ability to freeze the series' version of Bizarro in mid-air with minimal effort, are a courtesy detail. The fact that he is ''not'' infallible makes it even more worrying, as the events of the ''Forever Red'' arc in the sequel are precipitated by someone who's invisible to his precognitive senses, resulting in the world being turned upside down and the near-unleashing of [[spoiler: the Dark Phoenix]], an EldritchAbomination that on its last rampage destroyed a galaxy. And this time, there'd be ''two'' of them.

Super-trope of TemporalParadox. May result in TemporalSickness. Compare TimeCrash, HyperspaceIsAScaryPlace.

* In ''Film/XMenDaysOfFuturePast'', ComicBook/KittyPryde's MentalTimeTravel works by projecting one's consciousness into their past self long enough to alter the past. However, transferring a consciousness back too far into the past puts too much stress on the mind of the traveler, meaning that the only one capable of doing so is Franchise/{{Wolverine}}, whose mind can heal as it is damaged. Furthermore, if the connection is broken at the wrong time, the changes that the traveler made in the past take effect, meaning that changing the wrong thing could potentially leave the surviving mutants worse off in the new timeline.

* In ''Marooned in Realtime'', one person is trapped outside the bubble, so she ages to death while waiting for them to return after making a sign at where the camera is pointing. (The bubble pops and appears in a millisecond each year for them to see what is going on.)

* ''Literature/ThePeaceWar'':
** The bubbles of stopped time turn out to be dangerous in various ways, such as a war ship that manages to stop time while it is exploding, so when it exits the bubble it explodes. It could happen to any bubble, as they did not know which bubble contained what.
** In ''Marooned in Realtime'', one person is trapped outside the bubble, so she ages to death while waiting for them to return after making a sign at where the camera is pointing. (The bubble pops and appears in a millisecond each year for them to see what is going on.)

* Played to the hilt in [[Recap/RickAndMortyS4E1EdgeOfTomortyRickDieRickpeat an episode]] of ''WesternAnimation/RickAndMorty'' which cogently deconstructs why it's a rule that time travel is the one sci-fi trope the protagonists will never willingly indulge in. A chance encounter with a race of [[IntelligentGerbil alien snakes]] leads to them deciding to target Morty with time travel, with endless barrage of [[TerminatorTwosome assassins and guardians]] to fight a war over the Smith-Sanchez family. Rick decides to nip this in the bud by bootstrapping the snakes' history so they discover time travel before ever they ever met, which leads to the war shifting to assassinating snake [[UsefulNotes/AdolfHitler Hitler]]. All this draws the attention of the TimePolice, who RetGone the entire alien species.

However, not all time machines are like that. Some could get downright dangerous to use, because trivial mistakes in any time of time machine operation could get time travelers dead. Worse, the world or more could get destroyed by the time machine itself. There can be many reasons on why the time machine itself is dangerous. What if the time machine [[TeleFrag overlaps matter]] on its arrival? What if what powers the time machine itself is dangerous, due to various reasons from radioactivity, instability, or just sheer amounts of power necessary? Or, what if some of the time machine's physics requirements are dangerous? Or what if the time traveler is likely to end up [[TimeAndRelativeDimensionsInSpace someplace unsafe]], like anywhere but the surface of the earth?