Geocide in fiction

Update 2013-04-26

Thank you for reading "Geocide in fiction". This listing is no longer maintained. TVTropes' page Apocalypse How contains far more exhaustive lists of geocide scenarios from fiction, to which you can contribute freely and directly.

The complete destruction of rocky planets, gas giants, stars and frequently entire universes is a concept which dates back hundreds of years and has appeared in every significant medium. Here I aim to list the methods - real, imaginary, whatever - which have been used in fiction to destroy planets.

To be listed here, all one needs to do is exhibit the capability to destroy either an Earthlike planet or some superset containing at least one Earthlike planet. For example, anything capable of destroying the whole universe would be listed here. And it doesn't matter if the method ever actually gets used or not: as long as the capability is definitely there, it'll be listed here. Of course, extra-special attention is given to instances of genuine rocky planet destruction and extra-extra-special attention to examples of the Earth actually being destroyed in fiction.

Methods are divided up by medium and then by fictional universe, and are in no obvious order.

Films

Star Wars

Like this wasn't the first thing you thought of. The Death Star is a moon-sized space station which, alongside its astoundingly dangerous complement of turbolasers and TIE Fighters, sports a superlaser which when fired releases as much energy as the Sun does in thirty thousand years - enough to blast the (Earthlike) planet Alderaan to glowing shreds in a single, long-distance shot. An extremely in-depth discussion of the Death Star superlaser which incidentally includes some discussion of the order of magnitude of energy required to destroy an Earthlike planet can be found here.

A real laser of the same power output would, of course, only punch a hole straight through the Earth to the other side and do essentially zero damage to it apart from that. The Death Star is not a conventional laser, however, which is clear from the fact that the beam is visible; the technology is something else entirely.

Darth Vader in this movie describes the Death Star's capabilities as insignificant compared to the power of the Dark Side of the Force. Combined with Yoda's statements about size being irrelevant in the sequel movie The Empire Strikes Back, this would seem to imply that a powerful Sith or Jedi could destroy a planet ON HIS OWN. We never see a hint of this somewhat terrifying possibility becoming a reality anywhere in the movies, unfortunately.

The Extended Star Wars Universe (consisting mostly of books taking place after the original trilogy, but a lot more besides) augments this list considerably. The Sun Crusher is a relatively small ship which carries a small number of missiles each of which is tough enough to shoot into the centre of a star and cause it to go nova, which would certainly annihilate any nearby Earthlike planet. (Side note: the Sun Crusher is intended to SURVIVE the resulting explosion!) Centrepoint Station can destroy a planet via either destroying the sun it's orbiting, or moving it through hyperspace into some hazardous location i.e. a sun, a gas giant or a black hole. Knights Of The Old Republic's "Mass Shadow Generator" artificially increases the gravitational pull of a planet, destroying the planet Malachor V - though in reality an increased gravitational field would actually serve to make any planet much harder to destroy. Appearing in the Star Wars comic books are things called World Devastators which basically consume and process entire planets in elemental furnaces, as well as an object called a Galaxy Gun which is a beam weapon capable of destroying planets via "nucleonic chain reactions" from anywhere else in the same galaxy. In addition, the sentient planet Zonoma Sekot is able to move under its own power (!) and Force-capable (!!) - its destructive capabilities, therefore, are huge and uncharted.

There is also one instance in the comic books of a Sith Lord using "Sith Alchemy" to slam a pair of stars together, something we have established as fatal to nearby planets.

Titan AE

The Drej mothership in this movie destroys the Earth early on, or so I am told.

Transformers: The Movie

Unicron, a gigantic, planet-sized Transformer, chews up whole planets in this movie.

Supernova

This hilarious piece of non-science involves a bomb containing 9th dimension material being detonated near a supernova. Due to the property of 9th dimension material, the explosion would continue until all 3rd dimension matter in the universe was expended - taking out the Earth along with the rest of the universe.

Dogma

Find some angels that have been banned from Heaven forever. Find a church that offers general absolution. Send the angels to the church, thus proving God to be wrong and causing all of existence to instantly cease.

Dark Star

This John Carpenter movie contains a little geocide, or so I'm told.

Battle Beyond The Stars

There's a weapon here called a "stellar convertor" which can convert a planet into a star in this movie.

Plan 9 From Outer Space

Apparently, humanity is close to creating a "solaranite" or "solarbonite" bomb, capable of "exploding the particles of sunlight" and ultimately destroying the universe. The aliens in this movie actually begin raising the dead as part of their plan to conquer humanity and preventing the bomb being created - their ninth plan, in fact, the previous eight having failed. Get it?

Interestingly, the aliens are ultimately defeated in this movie, which leaves room either for Plan 10, or for humanity to actually build that bomb...

Men in Black 2

A tiny spaceship is seen blowing up several planets with an unidentified ray in the opening scenes of this film.

Star Trek II: The Wrath Of Khan and Star Trek III: The Search For Spock

The Genesis device featured in these movies may be capable of tearing a whole planet to shreds; however, it promptly reassembles them into another planet. This new planet is unstable and explodes in STIII.

Star Trek: Generations

Soran blows up two entire star systems including inhabited planets in the course of this film.

Soldier

The planet Arcadia 234 is blown up with a "planet killer" in the closing parts of this movie.

Forbidden Planet

Altair IV is blown up by ancient Krell technology at the end of this movie.

Videogames

Perfect Dark

The Cetan megaweapon, dormant on the bottom of the Pacific Ocean for millions of years, would function as a strong nuclear force destabilizer when activated, nullifying the forces keeping quarks together in atomic nuclei and causing the entire planet Earth to revert to an expanding cloud of randomized subatomic matter. The device gets blown up before the end of the game, though.

Marathon

Failure to complete this game could result in the Earth being 1) blown up by an early nova induced in the Sun by the trih xeem or 2) dissolved along with the rest of the universe and time itself after the release of the W'rcacnter.

Kingdom Hearts

Find the heart of the world, and swarm it with beings of darkness called the Heartless. This would apparently do the trick.

Star Ocean II

An Earthlike planet is crashed into a giant body of energy and completely destroyed. (?)

Star Ocean III

It turns out that this universe (which does include planet Earth) is a gigantic Massively Multiplayer Online Game in which we are all NPCs. Certain scientific experiments become interpreted as attempts at hacking, annoying the mainframe's owners so much that they decide to erase the entire Milky Way.

It's unclear whether Earth actually gets destroyed, though. And apparently the beings which destroy planets are relatively easy to defeat in the game.

Dead Space

This game is set aboard the USG Ishimura, a "Planet Cracker" class spaceships that destroys planets in order to extract valuable ore.

Metroid Prime 2: Echoes

This game is set on two planets, Aether and its evil dark dimension alternate twin Dark Aether, which is blown up by the end of the game.

Metroid Prime 3: Corruption

Culminates in the explosion of the Phazon planet, Phaaze.

Final Fantasy VII

Drain the Earth of all its 'lifestream'. This can be accomplished by Mako Reactors, which convert the lifestream to electricity. As the lifestream is drained, living things start dying off, and when the process is complete, the Earth itself will die and break up. This assumes, however, that the planet featured in this game IS the Earth, which is not explicitly stated. If this is not the case, this method probably would not work on Earth itself.

The villains Sephiroth and Jenova in this game plan to turn their planet into a spaceship and "cruise the universe", which means they have a method for moving the Earth, which would facilitate many other methods for destroying it.

Katamari Damacy

Roll up the entire Earth into a ball and catapult it into space to become a star! La la la.

Spore

This game allows planets to be turned into stars using a Planet Buster weapon.

Super Metroid

The planet Zebes is rigged to explode by the Mother Brain in this game.

Metroid Fusion

A planet is blown up in the finale of this game.

Master Of Orion II: Battle At Antares

The Stellar Converter is a weapon you can acquire in this game, capable of blowing up enemy planets in a single shot.

Space Empires V

It's called a Tectonic Bomb.

Space Quest: The Sarien Encounter

The inhabitants of the planet Xenon, in the galaxy of Earnon, discover their sun is going to essentially shut down due to natural reasons, and start researching for a method to create a new star from a nearby planet in order to stay alive. (Of course, both would still orbit the dead star, which would make light and energy to shift in interesting patterns.) They come up with a machine called the Star Generator. After the first test of the Generator, which is carried onboard the starship Arcada, the Sariens, an evil race, decide they want the Star Generator for themselves, and proceed to steal it. Their intent, of course, is to use it to threaten other races into submission. Hero Roger Wilco sets out to locate the Star Generator and succesfully destroys it. The Star Generator is shown in the game, but not in action, and its mechanism isn't even described.

Commander Keen

"Tantalus rays" are shown destroying the Earth in one episode of this series. Later, a weapon called the Omegamatic is described which could destroy the Milky Way galaxy. The main villain of the series intends to destroy the universe, although how is unclear.

Mortal Kombat 3

The character Smoke has a fatality called "Armageddon" which blows up the world. This is arguably the least climactic planet-destruction on this list.

Books

The Night's Dawn trilogy (The Reality Dysfunction, The Neutronium Alchemist and The Naked God), by Peter F. Hamilton

A planet or star - regardless of mass - could be induced to go nova/collapse into a black hole via injection of a Neutronium Alchemist. The Neutronium Alchemist is a unique device in this universe which is ultimately used to cause a nameless gas giant to go nova.

The Hitchhiker trilogy (The Hitchhiker's Guide To The Galaxy, The Restaurant At The End Of The Universe, Life, The Universe And Everything, So Long And Thanks For All The Fish and Mostly Harmless), by Douglas Adams

A Vogon Constructor Fleet carries enough destructive capability to destroy any rocky planet they encounter in the process of building hyperspace bypasses. The Hitchhiker trilogy has appeared as a radio series, a series of books, a television show and a movie. (I list it here under books since the books form the most extensive single continuity.) In each, the Vogons destroy the Earth very early on, but the methods shown differ. In the radio series, the Vogons use demolition beams and the process takes "slightly less than two of your Earth minutes" (about twenty seconds in the show). In the movie, no visible weapon is employed, and roughly ten thousand Vogon ships, arranged roughly uniformly to enclose the planet, carry out the destruction basically instantaneously.

There are other methods in the Hitchhiker universe. A planet could be potted into a black hole in a game of intergalactic bar billiards. Ford Prefect's father was the only survivor of the Great Collapsing Hrung Disaster of Gal./Sid./Year 03758 which otherwise wiped out his home planet of Betelgeuse Seven, though it's unknown whether the Disaster destroyed the planet entirely, or indeed what a Hrung is, or why it should choose to collapse on Betelgeuse Seven particularly. The amnesiac Grebulons in Mostly Harmless have a warship with the destructive power to destroy a planet, which indeed they do, after being manipulated by the Guide Mk 2 (which itself does not appear to wield any such power except indirectly through reverse temporal engineering, as here). Hactar's supernova bomb would take the whole universe out including the Earth, if activated. The Infinite Improbability Drive has been known to change whole planets into banana fruitcake and also, therefore, has the power.

It is theorised that if anybody discovered the Question to the Ultimate Answer Of Life, The Universe And Everything then they would cancel each other out and take the universe with it. It is also suggested that if anybody ever discovers what the universe is for, and why it is here, it will instantly disappear and be replaced with something even more bizarrely inexplicable. These last two are however only theories, even within the Hitchhiker universe.

The Lensman series (Triplanetary, First Lensman, Galactic Patrol, Gray Lensman, Second Stage Lensman, Children Of The Lens and The Vortex Blaster) by E. E. "Doc" Smith

In this fictional universe it is possible to neutralize the inertia of an entire planet - and fling it about like a stone on a string. The possibilities are endless - flinging the Earth into the Sun would be a piece of cake, but crushing a planet between two other planets is also an appealing proposition.

Then, of course, you have the Negasphere, a planet-sized object made of negative matter (not antimatter). A tractor beam pushes it, a repulsor pulls it. Upon contact, any matter becomes negative matter and is added to the sphere...

Stranger In A Strange Land, by Robert Heinlein

Here, some psychic Martians use their psychic powers to remove a portion of a planet's core, leaving void and causing it to implode.

Legion Of Space, by Jack Williamson

AKKA is a planet killer in this novel.

A World Out Of Time, by Larry Niven

This book features the Fusion Candle technique detailed under Ripped apart by Jupiter, only this time it's used to move Neptune. It wouldn't be hard to move Neptune towards Earth in this case.

The Nine Billion Names Of God, by Arthur C. Clarke

Program a computer to enumerate and pronounce all of the nine billion names of God, thereby ending the universe. (I believe this is based on what Clarke thought was a real Buddhist belief, anybody have some more information?)

Iron Sunrise, by Charles Stross

Twist a knot in space, enclosing the heart of the Sun, resulting in an iron core, which the remaining layers of the Sun collapse upon, causing a nova. Or something.

Accelerando, by Charles Stross

In this book the entire Earth's mass is chewed up to make computer processors.

Starship Troopers, by Robert Heinlein

A "Nova Bomb" could "crack a planet in half", but obviously cracking a planet in half does not destroy it.

Temple, by Matthew Reilley

An element called Thyrium can be exploded to "completely destroy nearly a third of the Earth's mass" and also knock the Earth out of orbit. So, triple the dose and you're done.

When Worlds Collide, by Edwin Balmer and Philip Wylie

In this book, a Jupiter-sized planet wanders into the solar system, causing havoc and ultimately colliding with Earth. This is an example of the "Pulverised By Blunt Instrument" method.

Moonseed, by Stephen Baxter

A self-replicating inorganic machine/organism (potentially created for the task) called the Moonseed assimilates the Earth's elements and restructures them, eventually causing them to explosively decompose into a fine dust. Earth eventually becomes a collection of debris scattered about the solar system.

Mathematical Puzzles And Diversions, by Martin Gardner

This is the first book I ever saw the Tower of Hanoi puzzle in. The legend, if it is indeed even a real legend and not just a fabrication of Edouard Lucas, goes that there are some Brahmin priests who are in the process of solving a 64-disc tower of Hanoi puzzle, and when they succeed (which, optimally, will take around half a trillion years), the world will end.

Hunted Earth series (The Ring Of Charon and The Shattered Sphere), by Roger MacBride Allen

A massive particle acclerator built around Pluto's moon, Charon, is used to generate a gravity laser. When a test beam is fired at the Moon, an alien ring hidden inside it sucks Earth through a wormhole elsewhere in the galaxy where a race of aliens attempts (but fails) to hurl the Earth at a piece of an extraordinarily tough creature which evolved on a neutron-star, destroying them both.

Other planets and moons in the Solar System get chewed up quite a bit by the aliens' "world eaters" which use gravity control to rip them apart as part of the foundations for a new Dyson Sphere. Many other planets are implied to have already gone through the process to build an existing sphere.

Earth, by David Brin

A microscopic black hole is used in an attempt to destroy the Earth.

The Forge Of God, by Greg Bear

Aliens set off nuclear explosions at fault lines on the Earth's surface, weakening its structural integrity, before shooting a slug of neutronium and a slug of antineutronium to collide at its core, blowing the planet up.

The Sten Series (Sten, The Wolf Worlds, The Court Of A Thousand Suns, Fleet Of The Damned, Revenge Of The Damned, The Return Of The Emperor, Vortex and Empire's End), by Allan Cole and Chris Bunch

A planetbuster missile (the size of a starship, filled with antimatter) is used in the final book to reduce a planet to an asteroid belt.

The Cthulhu Mythos (too many books to name), by H. P. Lovecraft and others

The Great Old Ones and the Outer Gods both seem to be... well... in theory they could... alright, I'm not sure about these. Apparently they could destroy planets.

Year Of The Jackpot, by Robert Heinlein

Various cyclical waves (stock markets, women's skirt lengths, gold prices, etc.) all troughing at the same time - and the Sun goes nova as well.

The Commonwealth Saga (Pandora's Star and Judas Unchained) by Peter F. Hamilton

Heaven help you if you unleash a quantumbuster bomb, which converts particles' rest mass into energy and can destroy an entire planet.

The Well Of Souls series (Midnight At The Well Of Souls, Exiles At The Well Of Souls, Quest For The Well Of Souls, The Return Of Nathan Brazil, Twilight At The Well Of Souls, The Sea Is Full Of Stars and Ghost Of The Well Of Souls) and the Watchers At The Well series (Echoes Of The Well Of Souls, Shadow Of The Well Of Souls and Gods Of The Well Of Souls) by Jack L. Chalker

In this continuity, Earth and the rest of the universe are simulations running on a gigantic computer called the Well World, and could easily be erased, or reset back to the Big Bang.

The Perry Rhodan series (far too many novels to name, by far too many authors)

Geocide weaponry in this gigantic space opera universe includes:

The "Arkon-Bomb", which releases hard "Hyper-Radiation" causing the atomic nuclei of certain elements (standard setting is all elements heavier than neon) to undergo fusion. This initiates an irreversible snowball effect. The affected planet is covered in an unextinguishable atomic fire and completely destroyed in a matter of hours or days (depending on the setting).

The "Gravitation-Bomb" opens a very brief rupture to hyperspace, causing matter and energy - usually enemy ships, but sometimes entire planets or star systems - to be ejected uncontrollably into hyperspace.

The "Nova-Bomb" causes a star to turn into a nova in a matter of minutes.

The "Galaxy-Igniter" dissolves the gravity in the target galaxy, causing it to dissolve. A part of the galactic matter is turned to plasma during the process. This technology is not available to mortal civilizations, but only to the "Cosmocrats", the forces of order in the universe, who battle against the "Chaotarchs".

There are some Earthmoving techniques in this fictional universe, also. The "Sun-Transmitter" is a matter transmitter which can be made by harnessing the power output of two or more stars, and is generally used to move planets across intergalactic distances. Large fleets of tenders fitted with Traktor-Beams can also be used to move planets.

Galactic North, by Alastair Reynolds

"Greenfly" are unstoppable terraforming machines which render every planet in the universe into biospheres, wiping out every civilisation in their path, in this story.

The Hyperion Cantos (Hyperion, The Fall Of Hyperion, Endymion and The Rise Of Endymion) by Dan Simmons

A microscopic black hole at the centre of the Earth features in these novels, though Earth is saved from being destroyed in this way.

2010: Odyssey Two, by Arthur C. Clarke

In this book the planet Jupiter is chewed up and turned into a star by self-replicating monoliths.

Starhammer, by Christopher Rowley

The Starhammer.

Television shows

Star Trek

In the TOS episode "The Doomsday Machine" the starship Enterprise encounters a machine which eats planets. In ENT, the Xindi are capable of destroying the Earth too, and so are Species 8472 from Voyager, and omega particles also from Voyager, and the Q from TNG. In DS9 a Changeling Infiltrator attempts to drop a device into Bajor's star to make it go supernova.

StarTrek.com has its own page dedicated to planet killers.

Stargate SG-1

Open a wormhole in the Sun, causing it to lose a whole load of mass in a short time, and go supernova.

Or open a wormhole connection to a Stargate on a planet being eaten by a black hole, causing Earth to be eaten as well.

Or convince the Ori to turn Earth into a black hole to power their so-called "Supergates". This has happened twice in the show so far.

Stargate Atlantis

The experimental Project Arcturus power source used by the Ancients has been known to lay waste to whole solar systems when implemented incorrectly.

Lexx

The Lexx - a spacecraft - is in this show the most powerful ship in the two universes (light and dark), and capable of destroying a planet.

The entire light universe (which doesn't contain Earth) is destroyed in this show when it is entirely converted by self-replicating Mantrid drones INTO more Mantrid drones. Mantrid then commands his drones to chase the Lexx (the only unconverted matter), with the massive shift in mass causing the entire universe to collapse on itself. The same method would probably work on the dark universe, specifically Earth.

The Earth ultimately gets shrunk to the size of a pea when some people create a black hole in a particle accelerator while trying to measure the mass of the Higgs boson.

Buffy The Vampire Slayer

Something something evil Willow something something black magic something.

Babylon 5

Probably the First Ones could do it.

A Vorlon Planet Killer actually leaves survivors on the surface of planets it attacks, so no go there. (On the other hand, the planet Arcata 7 is reported as "not there anymore" after being VPKed, so who knows?

Apparently Shadow missile drills don't do more than give a rocky planet "anomalous surface details", so no go there either.

A planet could, however, be wiped out by unscrupulous individuals opening a few jump points inside the Sun, draining it of mass, causing it to go nova.

Doctor Who

Drain the Atlantic ocean into the Earth's core, setting off an explosion of superheated water vapour! (Note: this would not actually work.)

Marvin The Martian

Four words and a serial number: Illudium Q-36 Explosive Space Modulator. Result: Earth-shattering kaboom.

Andromeda

A planet is seen in this show which has been blown up by exotic matter from a Slipstream Core (that is, an FTL drive which was shot at it).

The ship Andromeda Ascendant in this show is armed with 40 "nova bombs". One of those can make an ordinary star go nova. The implications for any nearby planet are left as an exercise for the reader. These can also be used to tear apart a planet directly, though this is less spectacular.

Invader Zim

Pump all the magma out of the Earth's core. Then fill it with snacks.

Alternatively, install gigantic television screens enclosing all of Earth, and put a standard day/night sky effect on those screens to dupe the mindless masses into thinking all is well... while you hurl the Earth into the Sun.

Futurama

Fill the interior of a planet with dark matter - then mine it all until the planet implodes.

Red Dwarf

A certain explosive is seen in this show which can cause a gigantic solar flare to knock a planet several hundred million miles across a solar system. Easy way to get Earth to Jupiter, aye?

Comic books

Marvel universe

I'm less well-acquainted with the Marvel Universe.

Any of: Galactus, the Beyonder, Molecule Man, any unscrupulous individual with a Cosmic Cube, the Living Tribunal, Eternity, Thanos (or anybody else with the Infinity Gauntlet), Dark Phoenix, Captain Marvel III, the Celestials, the Infinites, Surter and the Ultimate Nullifier could destroy a planet if they were so inclined. More info on these may come along when I can find the time to do some research.

DC universe

The Spectre is the agent of God's vengeance on Earth. Obviously he could destroy a planet if he became sufficiently motivated.

The Quintessence is a group of five immensely (infinitely?) powerful beings, comprised of the Phantom Stranger, Zeus, Highfather, Ganthet and Shazam. All of these are nominally good guys, but who knows?

Any the many Green Lanterns would be capable of destroying a planet with just his or her power ring: Kyle Rayner is on record as having destroyed the planet Oa by exactly this method.

The planet Krypton is well-recorded as having been destroyed, but this was a natural disaster and an isolated incident - the principles at work there probably couldn't be extended to destroy our Earth. The planet Xanshi was destroyed when a force known as Anti-Life placed a yellow bomb on its surface whose explosion was powerful enough to hurl it into its sun, so this probably could work on Earth.

The Anti-Monitor is on record has having destroyed entire universes by the hundred before ultimately being beaten.

Anime

Dragonball series (Dragonball, Dragonball Z, Dragonball GT)

Basically everybody from Vegeta in the Saiyan Saga onwards is supposedly powerful enough to blow up a planet with a gigantic ki blast. Power levels escalate exponentially as the series goes on (and on, and on) resulting individuals millions or billions of times more powerful, who could presumably blow up the Earth by merely blinking, though they seem somewhat, I don't know, reluctant to do so. It all gets rather silly. Still, one can't deny the fact that in the Frieza Saga, Frieza is shown destroying both the planets Vegeta and Namek.

The latter event is worth a little more detailed study. Frieza and our hero Goku are on the planet at the time, and it doesn't blow straight away. Over the course of the next few minutes, the sky darkens, lightning flashes, and the earth begins to split apart until it eventually explodes. I'd expect eruptions of lava and for the atmosphere to get incredibly hot, you know, explosions of molten rock and stuff, but hey, close enough. Of course, Dragonball Z being the astonishingly slow-moving piece of garbage that it is, the events of these five or so minutes end up spread out over six episodes - during which Goku has time to fight and defeat Frieza as well as exchange about an hour's worth of dialogue with him.

After training with the Elder God, Gohan becomes so powerful that he is forbidden to go Super Saiyan while standing on Earth, lest he destroy it by accident.

Earth is in fact destroyed in episode #262, "End Of Earth", by Kid Buu, but this is not an episode I've seen. It gets wished back into existence some time later.

In Dragonball GT it's revealed that if nobody collects all seven Black Star Dragonballs together, the Earth will be destroyed. In exactly as many words. I think the quote is, "I've discovered something very worrying. If the Black Star Dragonballs are not gathered together again within one year, the Earth will be destroyed!" Absolutely no explanation for this is given.

Actually it is due to negative energy mounting up from lots of previous wishes. Who knew?

Sailor Moon

Apparently it's possible that the Earth could be ripped apart by tendrils of black energy from a "Death Reborn Revolution" super-senshi attack in this particular animated universe.

Space Runaway Ideon

Ideon, the most ridiculously overpowered mech in animated history, is capable of slagging the Earth with ease.

Gunbuster

The so-called "Black Hole Bomb" in this episode seems to be a potential geocide, though it was nominally built to SAVE the Earth.

Tengen Toppa Gurren Lagann

The closing episodes of this show feature a mecha which is apparently the size of an entire galaxy.

Aha. What?

Miscellaneous

A band called Lemon Demon has an (awful) song entitled "The Saga Of You, Confused Destroyer Of Planets".

The universe of the tabletop turn-based strategy game Warhammer 40,000 contains a variety of entities capable of reducing a planet's surface to slag, though fewer capable of destroying a planet entirely. The Tyranid hive fleets can strip an Earthlike planet of so much mass that the orbit shifts significantly. The energy-feeding creatures called the C'tan or "Star Gods" can consume entire planets and star systems, and their enemies, the Old Ones, are equally powerful. The Battlefleet Gothic rulebook refers to a "planet killer" spaceship capable of reducing a planet to asteroids using an energy blast lasting about half an hour. Three Blackstone fortresses have also been known to combine to induce a nova in a star.

Homestuck

Characters in Homestuck capable of destroying worlds include: Doc Scratch, Becquerel, GCat and another First Guardian who has not been seen but must exist, Lord English, Bec Noir (does so, in the form of Red Miles), and the author, Andrew Hussie, who has inserted himself into the story. Snowman's death can, and does, cause the destruction of a universe. The Tumor's detonation has enough energy to destroy multiple universes, let alone a planet. Its detonation caused the formation of the Green Sun, into which entire universes could be thrown.

The Reckoning is doomed to be blocked, but if it was not, it could probably blast a planet into little tiny pieces. One could easily use an Alchimeter to create, say, a few million tons of antimatter. Jade could theoretically throw a rock, enlarge it to the size of a moon, and accelerate it towards a planet at near lightspeed.

The Scratch subtly changes the past, causing the present Earth to cease to exist. Many time shenanigans, such as the Timetables or basically anything related to The Felt, could be used similarly.

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