Apocalypse How/Class 5

Planetary-scale Species Extinction of all multicellular life. The planet may be fit for re-habitation.

Anime and Manga

 * The great fear of humanity in Neon Genesis Evangelion is Third Impact, which will complete the devastation of the Class 4 Second Impact. End of Evangelion ended with Third Impact and the resulting extinction of all Lilim (i.e. humanity and all other Earth species) via an Assimilation Plot, but it is outright stated to be reversible, and humans can exist as individuals again, if they really want to.
 * In Tengen Toppa Gurren Lagann, sets the Moon on a collision course with the Earth. Our heroes calculate that the impact will strip away the earth's crust, causing everything to die: if not from the impact, then from the superheated gasses released. It would cause the earth to become completely uninhabitable for at least a full year.
 * This happens at the Downer Ending of Saikano.
 * This is what's going to happen to the Magical World (population: 1.2 billion) unless the heroes Save! The! Day! in Mahou Sensei Negima. Specifically,
 * The future world in Yu-Gi-Oh! 5D's, which is shown both in the series and the movie..
 * Later volumes of Rave Master reveal that the world actually exists due to a Reset Button. 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.

Films -- Live-Action

 * This is the starting premise of Pandorum and initial best case scenario; then we find out the surviving humans wake up marooned on an ark after an offscreen Class X-2 event. It Got Worse when the personnel in charge went insane and left everyone in suspended animation for 900 years, where most of them evolved into zombie-like creatures that feed on the living. Oh, and the ship's reactor is melting down.
 * The worst case scenario in Armageddon involved this, if the asteroid "the size of Texas" would have hit, killing everything larger than bacteria (and most likely even the bacteria soon afterward, as the oceans would have boiled completely away).
 * This appears to be the setting in the Shane Acker film 9. The only things left? Sack people. And horrific machines.
 * The mostly-forgotten Japanese disaster epic Virus begins with the accidental release of a virulent 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 Gets Worse thanks to a Cold War doomsday machine.
 * The likely outcome if the Spaceballs had succeeded in stealing Druidia's atmosphere, though some life may have survived in the oceans.
 * This is apparently what the Final Protocol used by the Necromongers does to every planet they visit in Chronicles of Riddick.
 * It's implied that Godzilla going into nuclear meltdown in Godzilla vs. Destoroyah would incinerate the atmosphere causing all life on the planet to perish. It's only due to that prevents this from happening.

Literature

 * In Jasper Fforde's Lost in a Good Book, Thursday Next and her time-traveling father work to avert the nanomachine apocalypse that turns everything on Earth into strawberry Dream Topping on most of the timelines.
 * Stephen Baxter's Evolution does a Flash Forward near the end to the death of the very last lifeforms on Earth. This is so far in the future that the sun has begun to expand in preparation for its collapse into a white dwarf.
 * The eventual fate of Earth in Isaac Asimov's Robots-Empire-Foundation novels, due to gradually increasing background radiation, which starts as a class 0 event and gradually rises up to this level. It takes long enough that everyone eventually moves out into space.
 * Kurt Vonnegut's novel Cat's Cradle ends with
 * The Star Wars Expanded Universe featured a prototype Death Star and the Eclipse-class Star Destroyer, both of which mounted a powered-down version of the Death Star's famous Wave Motion Gun from A New Hope, which could "only" "crack the planetary crust" and would likely result in something like this.
 * In the backstory of the Mageworlds books by Debra Doyle, this happens to Entibor.
 * In The Killing Star, by Charles Pellegrino and George Zebrowski, all life on Earth above the level of bacteria is destroyed using a planet-wide relativistic bombardment.
 * In the story "Galactic North", a swarm of terraforming machines is slowly doing this.
 * CS Lewis's Narnia has the Deplorable Word, an incantation that instantly kills every living thing in the user's world except the user. Jadis of Charn used this long before becoming the White Witch; luckily, alternate magical laws seem to keep it from working on Earth or Narnia itself.
 * Hinted at in The Body Snatchers, by Jack Finney, when a Body Snatcher who's taken over the body of a friend states that the Body Snatchers only live five years, cannot reproduce and pretty much copy everything living, thereby turning whatever planet they invade (Mars and the Moon are mentioned) to lifeless blobs before launching off to seek out other living planets.
 * Arthur C. Clarke's The Songs of Distant Earth runs with the premise that humans calculate from unexpected scientific measurements only a brief few hundred years to leave the solar system due to stellar instability. Given that no technologies existed to send living humans away, the gesture was made of sending automated colonizers to populate other hypothetical worlds. Then things get a little weird.
 * Ethan I. Shedley's Earth Ship & Star Song begins with the premise that, despite largely successful efforts to ward off eventual extinction by environmental damage, the latest model projects only hundreds of years remain before life as we know it cannot be sustained even at minimum levels of consumption and entropy. As with Songs, above, the remaining humans alive decide to leave to escape this Class 5 destruction.
 * Arthur C. Clarke's Sunstorm (second book in A Time Odyssey) has the Firstborn redirected a planet and make it hit the sun around AD 0-10, which caused the sun to make coronal mass ejection, threatening to destroy the whole atmosphere.
 * In Saturn's Children this happens as part of the backstory. The robots who are left have enforced a strict quarantine on green goo and pink goo in the hopes that they can reconstitute the biosphere, particularly humans (they seem to be 3 laws robots and miss dealing with the first two).
 * Wilbur Whateley's journal, in H.P. Lovecraft's The Dunwich Horror, contains several references to the Earth's life being "cleared off", presumably to make way for Eldritch Abominations. Averted... but possibly still on the agenda of any surviving half-siblings of Wilbur's.
 * The Posleen War Series: happens so often due to uncontrolled population explosions that they have a specific name for it.
 * of the Old Kingdom Trilogy has this as his main goal. And he's done it before to other worlds before becoming Sealed Evil in a Can.
 * The Final Battle of John C. Wright's War of the Dreaming is expected to result either in this or Class 4 Event. For obvious reasons, not many people want it to happen.
 * The Road by Cormac McCarthy has lone bands of dying humans roaming the cold, gray, ash covered America, barren of all animal, insect or plant life. It is implied that once the last few survivors have cannibalized each other, there will be no life on Earth.
 * One of Alan Dean Foster's Humanx Commonwealth universe novels, Bloodhype, features the Vom, an Eldritch Abomination of possibly extragalactic origin that travels through space by enslaving sentient species and devours all life on planets it encounters down to the last microbe. Other novels in the series upped the ante - see the X-2 and X-4 entries.
 * David Drake's The Lord of the Isles series has several examples of this. In The Gods Return we get a glimpse of the Worm's (a giant slug-like monster) home planet. All life, including all other members of the Worm's species, has been consumed by the monster, leaving only a barren grey wasteland. Another novel features the Pack, a trio of life-consuming monsters from another plane of existence who have turned their whole universe into a barren desert. In "Mistress of the Catacombs" the main characters eventually wind up in an alternate-universe version of their own world where events much like the Ragnarok apocalypse from Viking myth have occurred. While some humans still survive, one character from the doomed planet makes it clear there are only months left until the final human is killed by a rampaging giant or other monster and the whole world is covered with ice.

Live-Action TV

 * Babylon 5 has . They use thousands of high-yield thermonuclear missiles which burrow into the planet's core and detonate in unison, reducing the entire crust of a planet to slag while it sucks away all useful energy in the process. While this is arguably more psychologically horrific and excruciating, actually sits higher up the scale at Class X.
 * Stargate SG-1 has the Dakara Superweapon, a wave that can reduce targeted matter (like organic life) to its basic components, effectively eliminating all such targets on the planet. If fired through the stargate while it's active, it can affect another planet. If the entire network is active, the wave can affect the entire galaxy.
 * Star Trek has a number of cases of this: an atmosphere is burned off in "The Chase", the Metrion Cascade killed everything on Rinax as detailed in "Jetrel", and if the whole thing wasn't a trap, the Tal Shiar/Obsidian Order attack fleet would have bombed the Founder's homeworld down to its core in "The Die is Cast."
 * The Season Six finale of Buffy the Vampire Slayer deals with Dark Willow attempting to burn the Earth to a cinder. Xander talks her down with the Power of Love.
 * * The Season Two finale had Acathla, a demon who would have sucked the world into Hell. This wouldn't actually have killed anyone - just subjected them to an eternity of torment.
 * "The Midnight Sun", a third season episode of the original Twilight Zone presented a scenario in which Earth's orbit had changed course, drawing the planet closer to the sun with each passing day.
 * The Doctor Who episode "Planet of the Dead". The resort planet San Helios was devastated and reduced to a desert by a swarm of stingray-like aliens.

Tabletop Games

 * This practically happens every other day in Warhammer 40,000:
 * Some of the more extreme forms of Exterminatus, including the most nasty virus bombs (the attack on Tallarn not only killed and disintegrated everything, it killed the microorganisms needed to break down and recycle the resulting horrible sludge of life. People in virus-proof bunkers survived, but the same thing happening to a place without those would be a definite Class 5).
 * Another variant essentially blows the entire crust open and turns the entire planet into a ball of lava. Ouch.
 * When the Tyranids finish with a planet, not only is it left a lifeless, airless, barren rock, but it's also significantly smaller than it was before the Tyranids started -- the bugs eat everything organic or consumable on the planet, down to the bedrock, and drain the heat from its core.
 * Necrons kill everything. Everything. Down to bacteria. Specifically, we have the World Engine, a Death Star-like capable of turning every single living thing on a planet into a cloud of atoms with a single shot.
 * The so-called "Tombworlds" are planets stripped of all life by the Necrons in ancient times to make them suitable for long-term Necron occupation/hibernation. Some of them were unknowingly terraformed by humans millions of years later.

Videogames

 * In Star Control II. The Shofixti race use their own sun as a kamikaze bomb, killing all but 18 Shofixti (2 male, 16 female) and utterly ruining their solar system (but hey, they destroy a third of the Ur-Quan fleet!). Amusingly, those 18 Shofixti were able to repopulate their species in three months. Not nearly as amusing are the Mycon Deep Children, which take Earth-like worlds and turn their crust inside out, transforming it into a "Shattered World" uninhabitable to all but the Mycon.
 * Fahrenheit (2005 video game) takes place during the buildup to a class 5.
 * Heroes of Might and Magic IV begins with two characters from the previous game meetings on the battlefield, and when their Artifacts of Doom touch, the atmosphere is instantly ignited, killing everyone except for a few people who managed to port to another planet or something.
 * In Homeworld, several races have Atmosphere Deprivation Weapons. These have the effect of setting the atmosphere on fire. If only one or two are fired, it only results in a Class 0 effect (the size of a continent) - however, it only takes a few to render the planet completely and permanently uninhabitable. It happens several times.
 * In the backstory, a vengeful Taiidan Admiral uses these on many populated Hiigaran worlds (though admittedly the Hiigarans had bombarded his planet with conventional weapons beforehand). He only stops because of a galactic outcry for peace.
 * In the first game, on the third mission, you return to Kharak (your home planet) after your first Hyprspace run... only to find it burning as a result of ADW bombardment. One of the most unexpected Doomed Hometowns ever, and is also a real Tear Jerker. Sure, Kharak was a tiny, almost inhospitable desert planet... but it was home. Add to that, the fact that almost the entire Kushan population was down there, leaving your Mothership and her fleet the last Kushan in the galaxy, and you really, really begin to hate the Taiidan Empire (who were responsible). Oh, and the reason? You broke a treaty that was four thousand years old, stating you couldn't develop Hyperspace technology, that not one single Kushan even remembered.
 * Then in Homeworld 2, set 100 years after the events of the original Homeworld, the Vaygr attack Hiigara with a massive fleet consisting of three Planet Killers. These are incredibly cool, but just happen to each carry a large payload of ADWs, which they try to drop on Hiigara. You have to destroy the missiles before they enter the atmosphere, and then use the Sajuuk's Wave Motion Gun to destroy them, because it is the only gun that even has a chance of denting them.
 * Lots of ways to get this in Master of Orion 2. Excessive bombing, especially with biological weapons ends like that. If you give Space Crystal a chance, it wipes your colony with Death Spores. When you fail to defend a colony from Space Amoeba, it devours everything and, after it finished its lunch, every planet in the system is toxic forever (or until Class X variant is applied).
 * StarCraft sees the Protoss initially doing this to every single planet that the Zerg has colonized, wildlife or Terrans notwithstanding.
 * Tabula Rasa started off After the End of human civilization on Earth with this. Recall the opening video? Remember Sarah Morrison's voice over saying "We never stood a chance?" Guess what--it wasn't the Bane's forces that we didn't stand a chance against. Turns out, the world militaries made quite a showing after the initial invasion--so rather than fight it out, the Bane dropped Ceres onto Earth. If you'd like an idea of how that worked out, look at the YouTube link to the Miracle Planet video in the Real Life example below this. Keep in mind, though ... the simulated impact in Miracle Planet involves an asteroid 500 kilometers in diameter. Ceres is 950 kilometers wide.
 * This is what will happen in The Legend of Zelda: Majora's Mask if you fail to prevent the moon from completing its suicidal fall after the three-day time limit.
 * Accidentally triggering this early is what lands War in the mess he finds himself at the beginning of the game in Darksiders. Oops?
 * The Player can doom the planet to this at the end of Fallout 3 by injecting the FEV. Oh... you think you're going to kill just the mutations currently around? What's to stop it from future life mutations, either natural or caused by the still-present radiation? It's a biological weapon, what did you expect? Congrats, your belief that you're shooting the dog doomed the world. You'll get your comeuppance by drinking your concoction in Broken Steel.
 * Glassing in Halo. Although it is possible to survive in bunkers.
 * Visas, in Star Wars Knights of the Old Republic 2 is from a world that was cleansed of life by Darth Nihilus, who used The Force to consume every living thing on the planet except her. One of the last story missions in the game is centered around stopping him from doing it to Telos as well.
 * This is what happens to Lore at the end of the Doomwood saga in Adventure Quest Worlds if you choose to.
 * The Doomwood II saga, and in particular the Adventure Quest Worlds: Zombies universe, has.
 * Considering that an Omnicidal Maniac dragon-thing of supreme power and malevolence is about to suck the world hollow, this is the best-case scenario for what Defiant Ascended are sent back in time to avert in Rift. (It's quite possible, or even likely, that it's far worse than that.)

Webcomics

 * In Homestuck any planet that will develop Sburb will be bombarded with meteors that're teleported away from Skaia during the reckoning. These meteors start out extremely infrequent and small, but will grow in intensity and size until the players of the game are to enter The Medium. After that point, the meteors will easily wipe out any and all life on the planet. However, the game will also send Exiles from the Incipisphere, whose purpose is to recolonize the planet of the players.

Web Originals

 * Tech Infantry has a the moon severely structurally weakened by having miniature black holes repeatedly fired through it, then a large starship crashed into the crater at a large fraction of the speed of light, shattering the moon into a billion pieces. The fragments of moon rock shower down onto the surface of the Earth, creating enough kinetic heating from the impacts to melt most of the surface of the Earth and boil the oceans.
 * In one Global Guardians story, the Guardians traveled to a world in which the criminal Mad Scientist Doctor XX had succeeded in eradicating all male life on the planet through a tailored virus. By the time the heroes arrived, the virus had died off... and the remaining human population (all female) had descended into Mad Max-style post-Apocalyptic barbarism due to the sure knowledge that the human race was doomed to utter extinction.
 * The SCP Foundation mentions a number of "XK class end of the world scenarios," most of which are kept vague because of [DATA EXPUNGED]. The most prominent to be described in detail, SCP-093, is one of these, possibly a borderline Class 6.
 * One of these scenarios ends with every inch of the Earth being buried under hundreds of miles of cake. No, really.
 * This is one of the endings in One Chance.

Western Animation

 * While technically not a human example, the Martians in Invader Zim worked themselves to extinction turning their planet into a giant spaceship. "Because it's cool!"
 * On Ben 10: Alien Force, Paradox shows the heroes a possible future where a time-warping entity has caused everything on Earth to age into dust. He claims it's their best possible future if the entity isn't stopped.
 * In the Futurama episode "The Late Philip J. Fry", Fry, Bender and the Professor end up in the year 1 billion, where all life on Earth is extinct and only an empty, desolate plain remains.
 * Might have been the ultimate result of Nightmare Moon's actions (as during The Night That Never Ends the entire planet will inevitably freeze over), but since Status Quo Is God...

Real Life

 * Arguably, this might have happened to Mars and/or Venus. Some of the most extreme worst-case global warming scenarios see Earth heading this way too, although this view doesn't have widespread support among even climatologists.
 * It's been estimated that Earth itself has experienced this several times (fortunately, all were at the time where life was only beginning to become complex before each event).
 * This is the likely outcome of any asteroid strike of a sufficient size larger than a few miles across: Earth's surface would be burned away or covered in magma, and the only survivors might be archaeobacteria deep within the earth's crust. Worst news? It'll eventually happen, since the death of the Sun will have the same effect.
 * The first episode of the Discovery Channel miniseries Miracle Planet demonstrated this using an asteroid around 500 km in diameter (that's smaller than the diameter of the above-mentioned asteroid from Armageddon) colliding with present-day Earth.
 * Most scientists predict that the final mass extinction will take place as early as 600 million years because by then the warming and expanding Sun will actually raise temperatures on Earth so much that all carbon dioxide will literally be stripped from the atmosphere. When carbon dioxide levels reach a low enough level, all plants will become extinct because plants need carbon dioxide to survive, and consequently the loss of plants will remove all oxygen from the atmosphere as well, and combined with even faster warming, will also end all animal life.