History Main / TimelineAlteringMacGuffin

** Once again, Toys/{{Furby}}-like toy called Beebo ends up being transported into the 10th century Viking colony in North America called Vinland. The Vikings form a CargoCult, treating Beebo as a god and interpreting its preprogrammed phrases as calls to war and conquest, resulting in all of North America to be New Valhalla in the new timeline (effectively conquering it centuries before Columbus stumbles on the continent). Mick ends up roasting Beebo with his flame gun, convincing the Vikings that Beebo is not a god.

[[quoteright:350:[[Film/BackToTheFuturePartII https://static.tvtropes.org/pmwiki/pub/images/bttf_sports_almanac.jpg]]]]
[[caption-width-right:350:Just bet on the winner and you'll never lose.]]

* The "Whispered" of ''LightNovel/FullMetalPanic'' are privy to "[[BlackBox Black Technology]]" -- devices they should be unable to design for decades or even centuries. It's extended their UsefulNotes/ColdWar clear into the 21st century.

** Possibly used when [[spoiler:Chao Lingshen produces what may or may not be a future copy of the Springfield family register]] as the ultimate party-breaking item. Whether it was real or not is irrelevant, since it was destroyed shortly after. She did, however, bring a number of real pieces of information and technology from the future as well.

** It could also make a [[spoiler:FridgeHorror; the family register didn't written because up until his death, ''Negi never made a family.'']] Of course, you could also argue that [[spoiler:Negi ''didn't'' write his family register for whatever reason, but it brings another UnfortunateImplications; what kind of life [[LawfulGood Negi]] had that he didn't have time to register his family, or worse ''had to not register his family?'']]

** The Gray's Sports Almanac in ''Film/BackToTheFuturePartII'' allowed Biff Tannen to become wealthy by placing bets on the outcomes of sporting events when his future self gave it to him in 1955[[note]]What makes it work is that the Ripple Effect ensures that the Almanac will recursively update to reflect the changes in outcomes as a result of his prior betting, meaning it'll always be accurate[[/note]]. He then uses the money to become a CorruptCorporateExecutive and ruin the lives of Marty (and everyone else in Hill Valley), forcing Marty and Doc to go back in time and stop it.

* The arm and CPU from the first Terminator in ''Film/TheTerminator'', left behind in the 1980s, brought about the rise of SKYNET. [[TimeyWimeyBall Well, sometimes.]] In any event, since the Terminator was sent back in time ''by'' SKYNET, this is also a StableTimeLoop... until it's broken by the destruction of the items in ''Film/Terminator2JudgmentDay'', which doesn't stop SKYNET from rising again in ''Film/Terminator3RiseOfTheMachines'' (where the novelization even implies that, despite the destruction of the items, what had already been researched was apprehended by the military, leading to SKYNET's creation). Yeah, TimeyWimeyBall.
* The Grays Sports Almanac version was parodied in ''Film/HotTubTimeMachine'', where Lou initially makes a ton of money betting on the 1986 AFC Championship Game between the Denver Broncos and the Cleveland Browns. Unfortunately for Lou, the ButterflyOfDoom (in the form of a squirrel that Lou had [[VomitIndiscretionShot vomited on]]) kicks in to derail John Elway's game-tying MiracleRally in the fourth quarter. And ''extra'' unfortunately for Lou, the terms of the bet were that not only does he give up all his earnings to the other guy, he now has to give Nick oral sex -- and the guy he made the bet with has a gun and won't take no for an answer.

* In the second episode of ''Series/LegendsOfTomorrow'', Vandal Savage finds a piece of the 21st-century Atom suit in 1975 Norway. Realizing its importance, he orders his people to reverse-engineer it, killing a scientist who claims that it'll take too long. Back aboard the ''[[TimeMachine Waverider]]'', the "Legends" find out that this development will allow Savage to move up his TakeOverTheWorld schedule by a century or so, showing a picture of Central City on fire in 2016. Fortunately, the team recovers the tech before Savage can make use of it.

* Xanatos' claim that he is a self-made man in ''WesternAnimation/{{Gargoyles}}'' is apparently very, very true; when he and several others end up transported back to ancient Scotland (it's a confusing tale), Xanatos takes a moment to take a single coin of the time period, seal it in an envelope, and date it to be delivered to himself when he would be a young man in the future. He would then use said coin to invest and grow into what would become his future extremely powerful multinational company. Which would raise the gargoyles. Who would end up with [[TimelineAlteringMacGuffin the Phoenix Gate]]. And he'd end up traveling back in time with them. [[StableTimeLoop To send himself a coin.]]

* In Creator/HarryTurtledove's ''Literature/TheGunsOfTheSouth'', in which time-traveling Afrikaners help the South win UsefulNotes/TheAmericanCivilWar, we have [[spoiler: ''The Picture History of the Civil War'', a simple history book. Its major influence is in revealing how the Afrikaners lied to the Confederates, particularly by claiming that the world of the future is an endless racial war between blacks and whites, as well as disproving the Confederates' belief that they would be VindicatedByHistory for holding African slaves. This is what drives the Confederates to openly oppose the Afrikaners, as well as leading to the passage of a bill that provides for the gradual, compensated release of the slaves.]]

-->-- '''Vandal Savage''', about a laptop, ''WesternAnimation/JusticeLeague'', "The Savage Time, Pt. 2"

* One episode of ''WesternAnimation/AmericanDad'' had Stan go back in time to prevent Creator/JaneFonda from ruining Christmas (in his opinion). A tape of disco's greatest hits is accidentally left behind, where it's discovered by the past version of Roger the Alien, who becomes insanely rich and then goes broke riding the rise and fall of the disco trend. In the end of the episode, the family complains that Roger is whining about disco, ''again'' (something he never did before in the series.)

* "Mimsy Were the Borogoves" is a classic sci-fi short story by Henry Kuttner (under the pen name Lewis Padgett). A scientist doing an experiment in time travel realises he doesn't have anything to send back, so he grabs some of his children's educational toys and sends them back to 1943 (when the story was written) where they educate a brother and sister how to move into another dimension, which they do before their father's horrified eyes.

** In yet another episode, when returning [[Creator/GaiusJuliusCaesar Julius Caesar]] to his own time, Nate allows the Roman to see a book on the history of the Roman Empire. Caesar snatches the book without Nate realizing it. Upon returning to the ''Waverider'', the Legends are shocked to find out that, with the book's help, Caesar was able to avoid his assassination and used the lessons in the book to ensure an unending reign for the Empire, which managed to conquer the entire world by the 21st century. Naturally, the book is recovered and Caesar is mind-wiped.

* In PreCrisis [[Comicbook/{{Superman}} Superman]] stories, it was well-established that changing the past was impossible. One issue of ''Comicbook/WorldsFinest,'' however, saw the time travelling villain Chronos acquire the means to "interactively" time travel, so he ''could'' change the past. Fortunately, he never gets the chance. Instead, [[Comicbook/{{Batman}} Batman]] gets sent back in time to the night his parents were murdered, tempting him to SetRightWhatOnceWentWrong at the expense of the future he knows. Fortunately, he resists the temptation, and Superman is able to bring him back to the present.

** The 2009 ''Film/StarTrek'' film:

* ''VideoGame/TheSims3: Into The Future'' features at least half a dozen ways to influence the future neighborhood of Oasis Landing. The two that play this trope straightest are introducing a {{Future Music}}al instrument to the present, or "pioneering" the design of future robots. [[BraggingRightsReward All you get for either accomplishment is a]] [[OurFounder statue of yourself]].

** In ''[[VideoGame/TheElderScrollsVSkyrim Skyrim]]'' the player gets to read one for the first time. If opened near a temporal rift known as the "Time Wound", the Scroll lets yousee an important piece of the past. If used anywhere else it, temporarily strikes you blind. The only reason why it only ''temporarily'' strikes them blind is because the Dragonborn's soul technically exists outside of time also. (Several more Elder Scrolls play into the plot of the ''Dawnguard'' DLC, though you'll only need to gather them there. A [[TheOrder Moth Priest]] will read them for you.)

* Xanatos' claim that he is a self-made man in ''WesternAnimation/{{Gargoyles}}'' is apparently very, very true; when he and several others end up transported back to ancient Scotland (it's a confusing tale), Xanatos takes a moment to take a single coin of the time period, seal it in an envelope, and date it to be delivered to himself when he would be a young man in the future. He would then use said coin to invest and grow into what would become his future extremely powerful multinational company. Which would raise the gargoyles. Who would end up with [[TimelineAlteringMacGuffin the Phoenix Gate]]. And he'd end up traveling back in time with them. To send himself a coin.

** The Gray's Sports Almanac in ''Film/BackToTheFuturePartII'' It allowed Biff Tannen to become wealthy by placing bets on the outcomes of sporting events when his future self gave it to him in 1955. He then uses the money to become a CorruptCorporateExecutive and ruin the lives of Marty (and everyone else in Hill Valley), forcing Marty and Doc to go back in time and stop it.

*** "Future's End" has a 29th Century timeship that was sent back to 1967. Interestingly, the 29th century technology helps create the "holo-emitter" the Doctor uses for the rest of the series, so the timeship was a TimelineAlteringMacGuffin to the 24th Century as well.

** In the first draft of ''Film/BackToTheFuture'' Marty revealed to 1955 Doc that all his crazy inventions could be cheaply powered with Coca-Cola (ItMakesSenseInContext... [[ItRunsOnNonsensoleum well, almost]]) so when he traveled back to 1985 he actually ended in an alternate reality where everything was a {{Zeerust}} 50's rendition of the future, with hovering cars and robots everywhere powered by Coca-Cola. The dystopic part? [[ALittleSomethingWeCallRockAndRoll No Rock and Roll!]]

*** Played with the trope [[spoiler:by a future Spock showing Scotty an equation that he would eventually create -- however earlier in the film the reason that future Spock is there is explicitly stated to be an AlternateUniverse, not a StableTimeLoop. Scotty had not only already invented the formula, but had tested his theory before. It went wrong, leading to his assignment at the remote outpost we see, but this could be part of the AlternateUniverse. Spock only shows Scotty a ''revised'' version of his theory, bringing his own discovery earlier into the timeline.]]

* The arm and CPU from the first Terminator in ''Film/TheTerminator'', left behind in the 1980s, brought about the rise of SKYNET. [[TimeyWimeyBall Well, sometimes.]] In any event, since the Terminator was sent back in time ''by'' SKYNET, this is also a StableTimeLoop... until it's broken by the destruction of the items in ''Film/Terminator2JudgmentDay'', which doesn't stop SKYNET from rising again in ''Film/Terminator3RiseOfTheMachines'' (where the novelization even implies that despite the destruction of the items, what had already been researched was aprehended by the military leading to SKYNET's creation). Yeah, TimeyWimeyBall.

** Once again, Toys/{{Furby}}-like toy called Beebo ends up being transported into the 10th century Viking colony in North America called Vinland. The Vikings form a CargoCult, treating Beebo as a god and interpreting its preprogrammed phrases as calls to war and conquest, resulting in all of North America to be New Valhalla in the new timeline. Mick ends up roasting Beebo with his flame gun, convincing the Vikings that Beebo is not a god.

* ''WesternAnimation/JusticeLeague'' villain Vandal Savage sends a laptop containing the history of UsefulNotes/WorldWarII to himself in the 1930s. With his advanced knowledge, [=WW2=]!Savage easily outwits the Allied forces, deposes Hitler and sets his sights on world domination. The present!league minus Batman (given RippleEffectProofMemory by being protected by Green Lantern's power when it was sent back) must go back in time to prevent this.

* ''Franchise/TheElderScrolls'': The eponymous [[TomeOfEldritchLore Elder Scrolls]] themselves. While not exactly a mundane item from the future, they are scrolls of unknown origin and number which simultaneously archive both past and future events; all that has happened, all that will happen (usually in the form of "If X happens, then Y and Z will happen, in that order"), all that ''could have'' happened. They require immense training in order to read and actually interpret anything useful, and have a high probability of causing blindness and madness in their readers. (Even those who merely study the ''nature'' of the scrolls, never actually reading a scroll themselves, are driven to complete madness with alarming regularity.) The scrolls have been used by the various Imperial Dynasties throughout history to help guide the Emperor in making decisions.
** What's more, they are absolutely and utterly immutable, such that they can change history, just by being read. In ''[[VideoGame/TheElderScrollsIVOblivion Oblivion]]'' the ultimate ThievesGuild quest involves stealing one in order to break a Daedric curse.
** In ''[[VideoGame/TheElderScrollsVSkyrim Skyrim]]'' the player gets to read one themselves. If used near a temporal rift it lets them see an important piece of the past; used anywhere else it temporarily strikes them blind. The only reason why it only ''temporarily'' strikes them blind is because the Dragonborn's soul technically exists outside of time also.

* Subverted in the Literature/DoctorWhoNewAdventures novel ''Just War''. Benny's history book, which details the entire course of World War II, falls into the hands of a Nazi officer. At first he dismisses it as a fraud intended to demoralize, then accepts its validity as the events it describes keep coming true -- but he is unable to get his superiors to listen to his warnings, and watches helpless as the Third Reich rolls on toward its historical end.

-->-- '''Vandal Savage''', ''WesternAnimation/JusticeLeague''

* ''WesternAnimation/JusticeLeague'' villain Vandal Savage sends a laptop containing the history of WorldWarII to himself in the 1930s. With his advanced knowledge, [=WW2=]!Savage easily outwits the Allied forces, deposes Hitler and sets his sights on world domination. The present!league minus Batman (given RippleEffectProofMemory by being protected by Green Lantern's power when it was sent back) must go back in time to prevent this.

** In ''Film/StarTrekIVTheVoyageHome'', Scotty teaches the 20th century plastic maker how to make "transparent aluminum", justifying it with the argument, "We know it was invented around this time, but we don't know the name of the man who invented it. It could have been him." The original script had Scotty saying that he knows that the manager would eventually go on to "invent" it, therefore giving him the formula created a StableTimeLoop.

* In the sequel to ''Literature/TheBookOfNightWithMoon'', a spin-off of the ''Literature/YoungWizards'' series, a book on modern-day engineering gets sent back into an AlternateUniverse [[VictorianLondon Victorian England]], enabling the British Empire to rapidly develop many forms of modern-day technology. Including nukes.