History ApocalypseHow / Class5

* In ''VideoGame/SolatoroboRedTheHunter'', [[spoiler:[[BigBad Baion]] plans to use Tartaros to initiate "CODA" early, it being a WorldSundering that would result in the [[WorldInTheSky floating islands making up the world]] being brought back down to the planet's surface, with all their inhabitants being fried to death as a result of passing through the volatile Plasma Cloud Sea. While Tartaros itself can only force the Shepherd Republic down to the planet, dialogue indicates that the activation of CODA would result in all other Juno being summoned from their dimensions and doing the same to all the other floating islands scattered across the world.]]

* In ''VideoGame/SolatoroboRedTheHunter'', [[spoiler:[[BigBad Baion]] plans to use Tartaros to summon all other Juno for them to initiate CODA, which would result in all the floating islands scattered throughout the world being brought back down to Earth, with all their inhabitants being fried to death as a result of passing through the Plasma Cloud Sea.]]

* ''Franchise/{{Godzilla}}'' fanfiction ''Fanfic/AbraxasHrodvitnon'': The author confirmed in a Tumblr post that if Ghidorah had completed its original rampage during [[Film/GodzillaKingOfTheMonsters2019 Mass Awakening]], there wouldn't have been much of anything left alive on Earth outside of the HollowEarth save for Ghidorah, the Titans under its thrall, and bacteria.

* ''Film/TheColony2013'': The GlacialApocalypse caused by [[TheNightThatNeverEnds a ceaseless global snowstorm blanketing the Earth's skies for years]] has annihilated the Earth's biosphere, with the exceptions of heated bunkers full of human survivors and (failing) crops and livestock, and possibly also with the exception of micro-organisms that could be preserved under the ice in stasis.
* ''Film/GodzillaKingOfTheMonsters2019'': It's speculated by Emma Russell in the film's {{novelization}}, and further confirmed by Monarch's projections in the novelization of [[Film/GodzillaVsKong the sequel]] that if King Ghidorah continued reigning over the Earth's Titans unopposed, then him commanding them to engulf the planet in a NaturalDisasterCascade and spreading [[WeatherManipulation massive superstorms]] globally would have thoroughly driven all life on Earth except for bacteria and Ghidorah himself into extinction within just a few years. And what's worse, Serizawa speculates in the ''King of the Monsters'' novelization that once Ghidorah has finished destroying the Earth's surface, he'll enter the [[HollowWorld Hollow Earth]] and do the same there.

** "[[Recap/DoctorWhoS30E5ThePoisonSky The Poison Sky]]": The Sontarans' AtmosphereAbuse (filling the Earth's atmosphere with a clone-feeding gas that is deadly to humans) would more than likely cause this for Earth's native life while the Sontarans can come in and convert the planet's landscape into a breeding planet for themselves in the aftermath.

* In the ''Doctor Who'' spin-off ''Series/TheSarahJaneAdventures'' serial "[[Recap/TheSarahJaneAdventuresS2E9E10TheTemptationOfSarahJaneSmith The Temptation of Sarah Jane Smith]]", this is implied to be the fate of Earth in the AlternateTimeline where the Trickster "sucked the life out of the world" in the 1950s. London is a grim, barren wasteland devoid of any plant life, and while some humans still exist as the Trickster's slave labor (using the remaining resources to build starships so he can invade other worlds), apparently the single small group who are seen are the very last humans.

->''"Collision with a body 10 kilometers or more in diameter constitutes an extinction-level event, or informally, "a planet-killer." The resultant shock wave encircles the planet, a rolling earthquake well off the Richter circle, and converges at Australia. Even the most strongly reinforced subterranean bunker anywhere in the world would collapse. The tidal wave is as tall as the ocean is deep]], and it moves over half the speed of sound, leaving behind a crater five miles deep where the Mid-Atlantic Ridge used to be. Meanwhile, the very chemistry of the biosphere would be disrupted, with nitrogen oxides precipitating in the form of acid rain over the next 10 years, poisoning every body of water on Earth. All life on the planet is wiped out, with the possible exception of simple anaerobic organisms inhabiting the deepest points of the South Atlantic, North Pacific, and western Indian Ocean floors."''

* ''Westernanimation/WhatIf'' has Ultron pulling off this when he managed what he couldn't in ''Film/AvengersAgeOfUltron'' and launch Earth's nuclear arsenal (and probably hunting surviving humans as well, Black Widow and Hawkeye being possibly the last two survivors). And then comes Thanos, Ultron kills him to get the Infinity Stones, and with the knowledge they provide decides to wipe out life on a ''universal scale'', mostly through Class X planet destruction. [[spoiler:And once the Watcher makes Ultron realize the existence of a Multiverse, he intends to do this on other realities as well, forcing Uatu to aseemble a group of Guardians of the Multiverse to stop him.]]

* ''Fanfic/AbraxasHrodvitnon'': The author confirmed in a Tumblr post that if Ghidorah had completed its original rampage during [[Film/GodzillaKingOfTheMonsters2019 Mass Awakening]], there wouldn't have been much of anything left alive except for Ghidorah, the Titans under its thrall, and bacteria.
* In ''FanFic/ClashOfTheElements'', after taking control of [[spoiler: Joe Dark]]'s body, the [[spoiler: Dark King]] set in motion events that would bring about one of these to [[Franchise/SuperMarioBros Plit.]]
* [[Franchise/TheSlenderManMythos In the Slender Man fic]] ''Fanfic/ByTheFiresLight'' the story ends with the Slender Man calling in other [[EldritchAbomination Eldritch Abominations]] to take Earth as their own and boot off anything already on the planet.

-->-- "The Earth Will Shake," ''TabletopGame/MageTheAscension''

->[[ColonyDrop Collision with a body 10 kilometers or more in diameter]] constitutes an extinction-level event, or informally, "a planet-killer." The resultant shock wave encircles the planet, a rolling earthquake well off the Richter circle, and converges at Australia. Even the most strongly reinforced subterranean bunker anywhere in the world would collapse. [[GiantWallOfWateryDoom The tidal wave is as tall as the ocean is deep]], and it moves over half the speed of sound, leaving behind a crater five miles deep where the Mid-Atlantic Ridge used to be. Meanwhile, the very chemistry of the biosphere would be disrupted, with nitrogen oxides precipitating in the form of acid rain over the next 10 years, poisoning every body of water on Earth. [[DownerEnding All life on the planet is wiped out]], with the possible exception of simple anaerobic organisms inhabiting the deepest points of the South Atlantic, North Pacific, and western Indian Ocean floors.
-->--"The Earth Will Shake," ''TabletopGame/MageTheAscension - Ascension'' [[note]]This, by the way, is the more optimistic of the two downer endings if things go completely to shit during this scenario[[/note]]

%%* ''Manga/{{Saikano}}'': This happens at the DownerEnding.

* ''Film/TheColony2013'': The GlacialApocalypse caused by [[TheNightThatNeverEnds a never-ending global snowstorm blanketing the Earth's skies]] has annihilated the Earth's biosphere, with the exceptions of heated bunkers full of human survivors and (failing) crops and livestock, and possibly also eoyj the exception of micro-organisms that could be preserved in stasis under the ice.

->'''Thanos:''' Where do you think he brought you?\\
'''Dr. Strange:''' Let me guess. Your home.\\
'''Thanos:''' It was. And it was beautiful. Titan was like most planets; too many mouths, not enough to go around. And when we faced extinction, I offered a solution.\\
'''Dr. Strange:''' Genocide?\\
'''Thanos:''' At random. Dispassionate, fair -- to rich and poor alike. They called me a madman... and what I predicted came to pass.
-->-- ''Film/AvengersInfinityWar''

* This happened to Thanos's home planet Titan as revealed in ''Film/AvengersInfinityWar''. Thanos claims that an OverpopulationCrisis caused the extinction event, but Peter [[OneSteveLimit (Quill)]] notes that the planet itself is off its axis and that gravitational pull is "all over the place", indicating that a lack of resources wasn't the only reason for Titan's demise.

Planetary-scale Species Extinction of ''all'' multicellular life. The planet may be fit for re-habitation, but in the meantime, there's nothing more complex than bacteria left.

* This is the theorized level of destruction caused by the [[MillionMookMarch Rumbling]] in ''Manga/AttackOnTitan''. [[spoiler:The Walls that protect humanity are not man-made, but in fact are made up of thousands, if not millions of mindless Titans the size of the Colossus Titan. The First King of the Walls erected them as a deterrent, threatening to use them to flatten the entire world and kill every single human, plant, and animal beyond the Walls. However, only the one with the power of the Founding Titan is able to wake these Titans and start the Rumbling.]] [[spoiler:Unfortunately for humanity, in Chapter 122, Eren Yeager unleashes the Wall Titans as part of his plan to save his people by exterminating all of humanity. Ultimately, however, it gets no further than 80%.]]
* Later volumes of ''Manga/RaveMaster'' reveal that the world actually exists due to a ResetButton. Prior to it, the world was one human away from Class 5. This one survivor used the power of Star Memory to reset the world. [[spoiler:But, since reality got tampered, Endless was created to try and jerk the world back to the Class 5 it was.]]
* This happens at the DownerEnding of ''Manga/{{Saikano}}''.
* Hades' plans for Earth in ''Manga/SaintSeiya'' was to create an eternal "Great Eclipse", so Earth would freeze over and all life would die, turning it into a dark world much like the Underworld.
* The future world in ''Anime/YuGiOh5Ds'', which is shown both in the series and [[Anime/YuGiOhBondsBeyondTime the movie]]. [[spoiler: Synchro Monsters overload Momentum, essentially recreating Zero Reverse on a much larger scale. By the end of Aporia's memories; of the four survivors, three are dead, leaving the partially/robotic Zone and no other sign of life on the planet]].

* The mostly-forgotten Japanese disaster epic ''Virus'' begins with the accidental release of a [[TheVirus virus]] that kills off all vertebrate life on the planet except in Antarctica, leaving pretty much only penguins and 800 or so scientists and base personnel. Then it goes FromBadToWorse thanks to a UsefulNotes/ColdWar doomsday machine.

* ''Westernanimation/WhatIf'' has Ultron pulling off this when he managed what he couldn't in ''Film/AvengersAgeOfUltron'' and launch Earth's nuclear arsenal (and probably hunting surviving humans as well, Black Wiodw and Hawkeye being possibly the last two survivors). And then comes Thanos, Ultron kills him to get the Infinity Stones, and with the knowledge they provide decides to wipe out life on a ''universal scale'', mostly through Class X planet destruction. [[spoiler:And once the Watcher makes Ultron realize the existence of a Multiverse, he intends to do this on other realities as well, forcing Uatu to aseemble a group of Guardians of the Multiverse to stop him.]]

* The Wiki/SCPFoundation mentions a number of "_K class end of the world scenarios" (XK, NK, etc), most of which are kept vague because of [[NothingIsScarier [DATA EXPUNGED]]].

* If atmospheric carbon dioxide levels ever drop below 150 ppm, most photosynthesis will stop, plants will die, and everything that depends on plants will die. How close did Earth come to such a disaster, and how recently? Well, during the several most recent glacial periods of the current Ice Age, atmospheric CO₂ levels dropped to 180 ppm -- that's only 30 ppm away from Armageddon. These glacial periods happen about every 100,000 years and the last one was a mere 20,000 years ago. We're all damned lucky to be alive. A few multicellular organisms that don't depend on photosynthesis, such as the giant tube worms found near deep-sea hydrothermal vents, may survive, making this more of a class 4.5

* This is the ''starting'' premise of ''Film/{{Pandorum}}'' and initial best case scenario; then we find out the surviving humans wake up marooned on an ark after an offscreen [[EarthShatteringKaboom Class X-2 event]]. It went FromBadToWorse when the personnel in charge [[GoMadFromTheRevelation went insane]] and left everyone in suspended animation for 900 years, where most of them evolved into [[ZombieApocalypse zombie-like creatures]] that feed on the living. Oh, and the [[TimeBomb ship's reactor]] is melting down.

* The Wiki/SCPFoundation mentions a number of "_K class end of the world scenarios" (XK, NK, etc), most of which are kept vague because of [[NothingIsScarier [DATA EXPUNGED]]]. The most prominent to be described in detail, [[http://scp-wiki.wikidot.com/scp-093 SCP-093]], is one of these, possibly a borderline Class 6. [[spoiler:And we know so much about it because it already happened.]]