Lost Superweapon

"Then they went out and played Charles Fort and the Atlanteans versus the Ancient Masters of Tibet, but the Tibetters claimed that using mystic ancient lasers was cheating."

— Good Omens

Almost no matter what your level of military tech — javelin, arquebus, phased plasma rifle in the 40 Watt range, quantum black hole, whatever — it's nowhere near as good as it was in your great-great-granddad's day. In those days, men were real men, women were real women, and hideously powerful destructive forces were... better than this modern muck, with glowing runes and everything. This could be despite the apparent primitive nature of the society at the time. More rationally, it could also be the cause of the primitive nature of the society immediately following...

In any event, unlike its cousin the Ancestral Weapon, the Lost Superweapon is lost, not just possessed by someone in secret. (For the latter, see Superweapon Surprise.) Also not to be confused with the similarly named but unrelated Forgotten Superweapon, which is about anything useful that's possessed by a character and not used until later.

Lost Superweapons are generally a type of Plot Coupon and found in fantasy novels and video games, and almost as often in Science Fiction and Space Opera, if the setting involves Precursors. If the Lost Superweapon has become a notable part of the landscape, then it is a Weaponized Landmark. If it was lost with the intent of it never being found again but is found anyway, it's a Dangerous Device Disposal Debacle. Usally involves Ragnarök Proofing in order for the weapon to survive so many millienia.

See also: MacGuffin, Artifact of Doom, Older Is Better, Super Prototype, Lost Technology and Dangerous Device Disposal Debacle. Compare Fling a Light into the Future.

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Examples:

Anime & Manga

• Mazinger Z: Mykene Mechanical Beast. Old myths assured an ancient, allegedly lost Greek civilization called Mykene lived on the island of Bardos used metallic giants shot flames from their chests to defend their land. Big Bad and Mad Scientist Dr. Hell pondered maybe the myths might be true. Unfortunately for everybody, the old legends were indeed right, and he found an army of ancient, forgotten Humongous Mecha under the ruins of the island. However it is a subversion, since like it was seen in Great Mazinger, the Mykene civilization still existed, and throughout millennia had dramatically improved their technology, and compared with their newest mechas, the giant robots Dr. Hell found were ancient, outdated, mountain sized piles of scrap.
• One Piece has the three Ancient Weapons Pluton, Uranus, and Poseidon. Each one is said to be so powerful they make the Buster Call ^note  An attack in which the Marines summon ten Battleships to completely annihilate an entire island look mundane by comparison. Only one of each weapon currently exists in the world, but all three of them are hidden. The only way to find them is to decipher the texts of the Poneglyphs, large indestructible stone tablets left behind by an ancient kingdom that existed 800 years ago. However, deciphering the Poneyglyphs was declared illegal by the World Government partly because of the threat posed by the weapons. So far, we know of two weapons and where they are located. Pluton is a Battleship that is hidden somewhere in Wano Country, whose location was revealed by the Poneglyph in Alabasta. Poseidon is the Mermaid Princess of Fishman Island who has the power to control Sea Kings, whose location was revealed by the Poneyglyph in Skypiea. ^note  It's also revealed that Pluton was originally built by the shipwrights of Water 7 several centuries ago. The shipwrights kept the original Blueprints and secretly passed them down through the generations. The reason they did this was the fear that if someone were to revive the original Pluton or any of the other Ancient Weapons, the only means the world would have of defending itself was to build a second weapon to counter the first one. Although the ability to recreate Pluton was lost forever when Franky purposefully destroyed the Blueprints in the Enies Lobby Arc to prevent it from falling into the hands of the World Government.
• The God Warriors of Nausicaä of the Valley of the Wind.
• The Saint's Cradle of Magical Girl Lyrical Nanoha StrikerS.
  • And Ixpellia, who was in suspended animation for hundreds of years.
• Macross Zero centers around a Protoculture artifact known by the UN as "AFOS" and by the native Mayan islanders as "the bird-man". The militaries of both the UN and Anti-UN believe it is a powerful weapon and wish to use it, while the islanders believe that the bird-man is an ancient deity whose awakening will trigger the end of the world. The truth is a bit of both: the Protoculture did not want humanity to repeat their mistake of bringing war to the greater galaxy. The bird-man was an Ambiguous Robot they left behind whose job was to annihilate humanity if humans had not turned pacifistic by the time they achieved space travel. And it just got woken up in the middle of a World War.
• In Gargantia on the Verdurous Planet, the humans on Earth salvage what they can find underwater in wreckages and remains of ancient human civilization. They end up finding things such as laser cannons and railguns, which are much more advanced than the guns and artillery they've been relying on. And despite said lost weapons, all of that pales in comparison to what Ledo and Chamber, his AI mecha support, have. Which makes sense because said lost weapons were very old precursors to what was eventually built into Chamber, after the two were stranded during a retreat from a battle in outer space a long distance away from Earth.
• Attack on Titan:
  • The millions of colossal Titans entombed inside the Three Walls their original purpose was to deter any attack from outside forces (especially from The Kingdom of Marley), as it's stated that if they're released they would lay waste to the entire Earth. It's also revealed that only someone with Royal blood and the Foundation/Coordinate Titan power would be able to control them.
  • The aforementioned Foundation/Coordinate Titan power is also this, as it dominates and towers over all the other Titan powers, can rewrite the memories of the Eldian people and even alter the composition of their bodies. Unfortunately it was sealed away by the Royal family and the series focuses on finding a way to recover it.

Comic Books

• Astro City has the Innocent Gun, a weapon left on Earth by alien Precursors as the final defense against an unspecified future threat. It was hidden in an ancient underground temple, and harnesses one of the fundamental powers of the cosmos.
• Star Trek: Early Voyages: In "Thanatos" and "Nemesis", Commander Kaaj leads a covert mission to the Temazi homeworld in order to obtain the ancient and extremely powerful weapons left there by Ancient Astronauts several millennia earlier. He hopes to regain the honor and glory that he lost when Captain Pike destroyed the Pharos siteworld in "The Fires of Pharos". The Federation learns of Kaaj's plan, though they are unaware of his specific involvement, and sends Pike, Spock and Dr. Boyce, disguised as Temazi, to prevent him from obtaining the weapons. The Klingon High Council sends a fleet of battlecruisers to the Temazi homeworld as Kaaj is a renegade and they believe that he intends to use the weapons against them.
• Superman:
  • War World: Superman and Supergirl have to destroy Warworld, a star-sized weapon-satellite built by a war-mongering alien race several centuries ago.
  • Kryptonite Nevermore: A mysterious instrument called the Devil's Harp that can steal someone else's powers and skills and transfer them to its owner was found hidden in an ancient buried city.

Fan Works

• The New Adventures of Invader Zim has an invoked example with the Meekrob device known as Project Domination. The other Meekrob were so offended by its existence that they imprisoned its creator and sent it to drift in space so no one would find it.
• Ace Lives is a one-shot collection with two:
  • Luffy's straw hat is the Ancient Weapon Uranus. It lands on the head of an unfortunate marine who isn't on good terms with Luffy, promptly takes over his mind and body and lays waste to the battlefield (at one point fighting Mihawk, Akainu, Kizaru, Aokiji, Garp, and Sengoku at the same time), distracting the Marines and allowing Luffy to save Ace almost entirely unopposed.
  • In the third Christmas Special, Luffy's Straw Hat either belongs to or is Frosty the Snowman. Yes, that Frosty the Snowman.

Film

• In Appleseed Alpha Olympus sends out a bioroid with cyborg escorts to destroy what turns out to be a prototype Spider Gun Platform. However Talos, a member of the team, decides to activate it for his own use, only to discover that it's a revenge weapon programmed to march on New York and destroy it if the war was lost and the city was occupied by the enemy.
• The Great Cannons in Legend Of The Tsunami Warrior, which sank to the bottom of the sea and were retrieved by a band of pirates. An usual example in that they were only lost for a couple of decades.
• Gamera and the Gyaos in Gamera: Guardian of the Universe. The Gyaos were a biological superweapon made by the culture which inspired Atlantis that turned against their creators. Gamera was created to counter them and reawakens in modern times when the Gyaos become active again.

Literature

• Star Wars Legends:
  • The novels have the entire solar system of Corellia, made of giant spaceships disguised as planets with the tiny station of Centerpoint being the control center. Said spaceships can attack with their giant repulsors/engines, and Centerpoint is able to warp gravity across the galaxy to decimate an entire alien fleet. Oh, and Centerpoint can also make stars go nova and cut off the Corellian system from access to hyperspace. It's indicated (though never attempted) that by using the planetary repulsors to boost Centerpoint's output, the station could cut the entire galaxy off from hyperspace, making it all but impossible to travel between star systems. Given how essential interstellar travel is in the Star Wars universe, this would be roughly equivalent to reverting Earth to the stone age at the press of a button. Subverted, in this instance, as there's reason to believe that the Precursors didn't originally build this particular Lost Technology to be used as weapons of war. In part, it was designed to make sure a Sealed Evil in a Can stayed in its can.
  • Other examples include the Sun Crusher (which was forgotten because it was built in a remote Imperial wormhole facility that was only known to three people outside the facility...only one of whom was still alive), the Katana Fleet (which was lost to hyperspace troubles) and the Lusankya (an entire Super Star Destroyer buried beneath Coruscant to use as a prison). It's never specified why the latter was forgotten, but the two theories offered in-universe are both horrifying: that Emperor Palpatine was able to block everyone's memories of its burying through the Force, or that he simply had all of the billions of witnesses killed.
    • Downplayed with the Katana Fleet: while it consists of 200 Dreadnought-class cruisers, in the scope of the universe it's a relatively small number of outdated if serviceable mid-range warships, and the only reason it's meaningful is that if Thrawn got his hands on them they would give him just enough numbers to start offensive operations against the New Republic and bring his strategic genius to bear. The New Republic eventually finds it... And discovers Thrawn has already recovered most of the ships.
  • The Eye of Palpatine, a largely autonomous superweapon predating the Death Star with the mission of destroying a colony of fugitive Jedi. It never completed its mission due to sabotage, and was forgotten by Rebels and Imperials alike (those that even knew about it in the first place) until mysterious forces cause its AI to suddenly awaken.
  • The Another Chance, an Alderaanian warship loaded with every military weapon on the planet when Alderaan decided to disarm itself, and sent off into deep space where it would be virtually impossible to find unless the Alderaanians really, really needed them again. The Rebel Alliance got hold of it at some point, and the arsenal within turned out to have grown in the telling a bit; mostly infantry weapons, outdated but still in working order, which went some way to replacing the material losses incurred at Hoth.
  • Person of Mass Destruction Irek Ismaren, a Dark Jedi with implants that allow him to control droids and computers. Virtually unknown even within the Emperor's inner circle until Children of the Jedi, then disappears from galactic history again until Luke encounters him again as Lord Nyax - 3 meters tall, wielding no less than 6 lightsabers permanently attached to his body.
• The Lord of the Rings is full of these. Indeed, the book is set against a backdrop of general technological decline. If you're going into battle wielding anything forged within the last 3000 years or so, you might as well run into an aeroplane propeller.
  • And, as the trope description indicates, the constant war that produced these weapons is indeed the reason that things have fallen so far. For all Minas Tirith is impressive, it used to be a border fort and is beside the ruins of the fallen city it used to protect.
  • A notable aversion is Narsil, the sword of Elendil. When it is reforged for Aragorn as Anduril, the elves actually improved on the original design, making it better balanced, lighter, and enchanted so that it could never break.
• Subverted in Alastair Reynolds' Revelation Space universe: In one book, several of the heroes spend most of the story on a race to track down and wield Lost Superweapons to turn on the remorseless alien foe. They probably hoped for better results than "none at all. But she went out with a bang".
• Alan Dean Foster's Humanx Commonwealth universe is loaded with Phlebotinum left behind by ancient civilizations, among them quite a few superweapons. Examples:
  • The title device in The Tar-Aiym Krang, which uses an entire planet as its power source and creates Schwarzschild discontinuities... ahem, miniature black holes that utterly annihilate anything they touch.
  • The Hur'rikku artifact in The End of the Matter, which uses a powerful stasis field known as Fixed Cosmic Inertia to slingshot itself through spacetime and punch a hole into Another Dimension, through which a "white hole" composed of pure antimatter is created. This is used to destroy rogue black holes.
  • Not satisfied with one Krang, the Tar-Aiym also built a weapons platform the size of an entire planet that contains hundreds of Krangs. Flinx discovers it in Reunion and spends the rest of the series searching for it. His attempt to use it ends up being a Worf Barrage.
  • And last but certainly not least, the Xunca. Not satisfied with destruction on a mere planetary or solar system scale, they constructed a weapon concentrating the energy of several million galaxies across multiple dimensions. It gets used.
• The title device in Larry Niven's The Soft Weapon.
• A large number of these in Mortal Engines, such as MEDUSA the city destroying laser and ODIN the Kill Sat.
• Only a 30-year backlog on this one, but Peter F. Hamilton's Night's Dawn trilogy has the incredibly awesome Alchemist, which disappeared when the strike force heading off to deploy it was destroyed shortly before the genocide of their home planet's population. It's recovered towards the end of the second book, The Neutronium Alchemist, and the (fairly accurate) physics is explained- and we discover that it can turn a sun into a black hole. That's the more humane setting.
• The Ma Wi Jung in Crystal Rain, though it's not exactly a superweapon, per se.
• In Life, the Universe and Everything, there was the Supernova Bomb. Invented by the supercomputer Hactar at the behest of the Silastic Armorfiends of Striterax, it was a junction box which would make every sun in the universe go supernova simultaneously. Hactar purposefully made it faulty because he calculated that there wasn't a conceivable consequence resulting from not setting it off which could be worse than the known consequences of setting it off, so... The Armorfiends disagreed, before destroying him and then, fortunately for everybody else, themselves. Hactar managed to survive in a reduced form, and many millennia later had the Omnicidal people of Krikkit rebuild the bomb before planting it on Arthur Dent, who very narrowly avoided setting it off.
• The Wheel of Time has a couple of these lying around. Most notably, there's the Choedan Kal, two artifacts so powerful that each of them is capable of not only destroying the world, but also causing serious damage to the fabric of reality itself.
• In Christopher Rowley's Starhammer, The title weapon is a huge skyscraper-sized tank carrying a weapon that blows up stars, instantaneously over unlimited ranges.
• Iain M. Banks's Against A Dark Background features a Lazy Gun as a MacGuffin. It's a physically inexplicable weapon of unknown origins and great power, and now it's lost and finding it drives the plot.
• The Hador-Haelic space forts from The Helmsman Saga. They are well remembered and in plain sight, actually, and still in pristine condition after thousands of years... it's just that no one remembers how to power the guns up.
• The titular artifact in Dark Heart. An ancient magical weapon, capable of killing gods, that was used by the winning side in Caliel's long-ago Godswar, then lost when the victors had a falling out after the war.
• Hidden among the Floating Isles in Shadow of the Conqueror is a colossal sunforge which can do things impossible with conventional sunforging, such as creating sunucles of seemingly unlimited size or sunforging darkstone. Only Daylen found the mastered the forge, and he speculates that the Floating Isles were created when someone used it to accidentally make a Fantastic Nuke that shattered them.
• The Stormlight Archive has the Dawnshards. We don't know exactly what they are or where they disappeared to, but some scattered references hint that they're what humanity used to destroy our first planet and Honor's visions imply that possessing them would give humanity a fighting chance against the Physical God Odium. In the novella Dawnshard, it's revealed that they are four ancient commands that were used by Adonalsium to make the universe, and were later used by the Shardvessels as part of a weapon to shatter them into sixteen pieces, then were used to destroy humanity's original homeworld in the Rosharan system. As of the end of that novel, one of them has been discovered and hidden within Rysn, who cannot use its power.
• Deconstructed and parodied in Always Coming Home. Set far into the future where humanity only retains a few technologies of their previous height, the Dayao discover schematics for bombers and other old world weapons and set about reconstructing them to gain dominance over their neighbors. However, fuel is long gone, they don't have enough metal to make more than a few, and synthesizing corn into biofuel creates a food shortage that collapses their civilization. Sometimes, there's a reason things are lost, and it's because there simply isn't infrastructure to make them anymore.
• Laszlo Hadron and the Wargod's Tomb: The eponynous Wargod is assumed to be this, based on both the name and its connections to the Sagittarian Empire's extinction two million years ago.
• In Isaac Asimov's The Stars, Like Dust, set in a Feudal Future of human interstellar colonization several thousand years from now, multiple people are trying to track down a document from Earth's history, which they are convinced contains the secret to an extraordinarily powerful weapon. One character Lampshades the absurdity of the idea, pointing out that pre-spaceflight Earth was "a primitive place, militarily speaking" and calling out as ridiculous the common notion of "lost arts and lost sciences" that somehow surpass those of the present day. Yet even he is not really convinced that the document in question does not exist—because someone has gone to the trouble of stealing it, which surely no one would do if it were worthless. It turns out the document in question is the United States Constitution, and the "strongest weapon in the universe" that can defeat the enemy empire—and destroy all the rest of the Galaxy's aristocratic and autocratic rulers (and the protagonists are themselves aristocrats of one sort or another)—is the idea of democracy.

Live Action TV

• The Dakara Superweapon in Stargate SG-1, which was originally used by the Ancients to seed all life in the Milky Way. Being the arrogant, Neglectful Precursors that they were, they decided that instead of dismantling the device afterwards, they'd simply leave it sealed inside of a mountain, guarded by a single locked door.
  • When the protagonists get their hands on it they use it the exterminate the entire Replicator species. Its suggested that it could be tuned to kill anything, or everything.

Tabletop Games

• In one Paranoia mission, the PCs discover a long-forgotten antimatter bomb capable of destroying the entire Complex, and have to keep it away from fanatics who would actually detonate it.
• This trope practically litters Exalted, with two major examples being the Five-Metal Shrike (a sentient warship from the First Age that is hinted to still soar the skies of Creation) and the Realm Defense Grid (an old superweapon which only one person has ever been able to master since the days the Solars ruled... and they ended up making that person Empress of the most powerful nation in the world once she was done with it).
  • FMS might be nice, shiny and theoretically operational by just a playgroup, but there are also some surviving Directional Titans it was designed to kinda "replace". One is currently an underwater city and another a giant freaking flying mountain. Estimated matter survival time around each of those deployed in combat: 1 tick. And it does take a city of operators to man.
• This was the original defining feature of BattleTech. The golden age of technology was some 300 years ago and everything now is patched-up, dumbed-down versions of the stuff the Star League had but the Successor States have largely forgotten how to make. Later subverted as the Successor States slowly recovered, putting them on par or beyond the Star league.
  • The interstellar Warships have gone back to being lost, after the Word of Blake Jihad concluded. Every faction still has a few, but all the facilities capable of building more were destroyed and nobody's bothered trying to rebuild them. Inside the game universe, it was considered too expensive and difficult to maintain the facilities and there weren't enough people with the skills necessary to do so anymore. Outside of the game universe, Word of God is that the developers considered them to be overpowered compared to everything else and therefore wanted them to no longer be a factor: the Humongous Mecha the game was supposed to be centered around risked being metaphorically and literally overshadowed if Warships continued being built and used by everyone.
• The Imperium in Warhammer 40,000 appears to have lost the ability to innovate. Apart from reuniting humanity the Great Crusade is also about finding STCs on lost colony worlds that describe how to build things the Empire lost the plans of in the Age of Strife. There are also superweapons knocking about that were built by mysterious ancients who tend to manufacture these awesome devices and then wander off with the instruction manual in their pockets never to be seen again.
  • The technology from the aptly named "Dark Age of Technology", which was really a Golden Age for humanity. One novel describes the Adeptus Mechanicus (a machine-worshipping cult and one of the forces keeping the Imperium running) and their ancient space ships, with one of them hooking up to the ship's systems, which accidentially reactivates the equally ancient weapons on board. In short, in a setting where a small fleet of space ships can destroy entire planets, they still managed to bring this trope, since the weapon activated turned out to be a kind of temporal rift space torpedo, which then destroyed a massive Eldar ship (about the size of the moon) in a single shot.
• There are enough of these floating around in Rocket Age that its a serious problem. Mostly left over from the war between Mars and Eris, they seem to crop up in most of the adventures.

Video Games

• In Journey, the creatures you encounter in the fifth and seventh levels are the machines responsible for starting a civil war against your ancestors. Only some units remained active after the war.
• Vegnagun, the semi-sentient, Earth Shattering Doomsday Gun from the final days of Final Fantasy X's Machina War, was sealed deep below Bevelle one thousand years ago. Then it goes missing.
• The plot of Indiana Jones and the Fate of Atlantis involves stopping the Nazis from obtaining the God Machine, a mysterious device invented by the people of Atlantis that can supposedly turn humans into gods using Orichalcum, but which was abandoned and forgotten for reasons unknown. The reason turns out to be that it doesn't work; at best you become a hideously deformed mutant, at worst you transform into a mighty Energy Being and then immediately evaporate into thin air because you have no physical structure anymore. Indy manages to piece this together when he discovers a hall filled to the brim with the mutated skeletons of failed test subjects, and subsequently defeats the bad guys by tricking them into testing the device out on themselves.
• Star Wars:
  • Unlike most other superweapons in Star Wars, the Star Forge in Knights of the Old Republic was built by the Rakata and lost when their "Infinite Empire" was overthrown, until it was rediscovered by Darths Revan and Malak.
  • The Dark Reaper was a superweapon created by the Sith during the Great Hyperspace War ^note 20,000 years after the fall of the Rakata and 5,000 years before the original trilogy that performed Vampiric Draining on a massive scale, draining the Force energy from every living thing around it and focusing it into lasers. It was rediscovered twice, first by the Sith Lord Exar Kun and again by Count Dooku/Darth Tyranus in Star Wars: The Clone Wars.
  • The race that built Iokath in Star Wars: The Old Republic had the construction of superweapons as their national pastime. When they inevitably wiped themselves out, they left behind multiple examples all over Wild Space, including a fleet of tens of thousands of warships piloted by networked droid captains, as well as six colossal war droids that the ancient Zakuulans worshipped as gods.
• Halo has lots of these, courtesy of the Forerunners:
  • The titular ringworlds, which kill all sentient life in the galaxy when fired at once.
  • Halo 4 features the Composer, which downloads organic beings and reconstructs them into mechanical Promethean Knights. Unlike most examples, it was not originally intended to be used as a weapon; even the "turn people into robots" part was not part of its original purpose.
  • Halo 5: Guardians: The titular Guardians, gigantic bird-like constructs buried in numerous worlds. Now they're all awakening from their 100,000-year-long slumber in order to police the galaxy again.
• Remember the Gaia Temples in Sonic Unleashed? The ones built centuries ago to house (and if needed restore) the power of the Chaos Emeralds? Well, apparently, Light Gaia/Chip can summon them to form the Gaia Colossus, the one integral component (aside from the power of the emeralds) needed to tame Dark Gaia and prevent The End of the World as We Know It.
  • In fact, this was Dr. Eggman's shtick from about Sonic Adventure to Sonic Unleashed (chronologically, about 1998-2008). Virtually every storyline had him digging up one deranged Eldritch Abomination—or One-Man Army, in Shadow's case—or another. Of course, they all had their own agendas, usually revenge on whoever imprisoned them in the first place.
• In StarCraft II, protagonists Jim Raynor and Tychus Findlay are hired to recover several seemingly benign-well, relatively benign-precursor artifacts for an interested party. As it turns out, the five artifacts are actually the parts of device capable of killing all the zerg an entire region of the planet Char, and curing zerg infestation.
• The contents of D-6 in Metro 2033, especially the MRLs used to destroy the Dark Ones' hive.
• Deconstructed in Metro: Last Light where Rangers are trawling the D-6 storage facilities for survival supplies, but all they can find are bioweapons stockpiles. Lo and behold, some of those bioweapons end up in the wrong hands and nearly cause a catastrophe.
• Guillo in Baten Kaitos Origins. It was lost after the defeat and death of Malpercio, and the Children of the Earth abandoned it, feeling that a weapon capable of killing a god wasn't something the new world would need.
• The B-plot of Mass Effect 3 involves the Alliance trying to recover a Prothean superweapon, the Crucible, to use against the Reaper invasion. There are only two wrinkles: one, it's some-assembly-required, given that they have only the blueprints; two, it is missing a crucial component, the Catalyst (which is why it didn't work for the Protheans) — which turns out to be the Citadel.
  • Mass Effect 3 deconstructs this trope, as the designs for the superweapon are revealed to predate the Protheans - and even their predecessors - with every cycle adding and improving to its design. The last several of those cycles built it out of desperation from recovered plans and had no idea what the hell it was actually supposed to do.
• The Cetan starship from Perfect Dark is a planet killer that has been resting on the floor of the Pacific Ocean for millennia. The plot revolves around a conspiracy to retrieve the weapon and use it on Earth.
• There are a few in the Homeworld games. Homeworld: Cataclysm has the Siege Cannon, a Wave-Motion Gun built millennia ago by the Bentusi and then abandoned when the Bentusi disarmed themselves. Also, Homeworld 2 has the Movers, the Progenitor Dreadnoughts and the warship Sajuuk, all built by the Progenitors before their disappearance. These are the ones the player can acquire, as all the games have one: the original Homeworld has the Junkyard Dog (the most annoying foe in the series, possibly a Progenitor Mover variant), Cataclysm has the Naggarok (and if the damn thing had stayed lost until you found a way to destroy it, the characters would have been happier), and Homeworld 2 has the Progenitor Keepers, the drones carried by the Keepers and the Planet Killers (these of unknown origin, but somehow linked to the Bentusi).
• In Pickle Wars, the hero is tasked with finding the secret stash of weaponry needed to defeat the aliens that have invaded Arcadia. The weapons are lost because Arcadia has achieved world peace and has not had any need for them in ages.
• In The Adventures of Massmouth, one of the artifacts to find is the "Eye of Mahan", created by a wizard for an ancient king. Although supposed to "take out entire legions of men", it didn't stop the kingdom from falling. It's also a subversion: for all its fame, it simply doesn't work at all, and probably never did. (You can pick it up as a weapon, but it does literally nothing.)
• A Yithian lightning gun is found in Call of Cthulhu: Dark Corners of the Earth just when it's needed most.
• Fallout 3 has Liberty Prime, a giant robot originally built for the Anchorage Reclamation in 2072, but kept idle due to power supply difficulties. After the bombs fell, it stood forgotten in the Pentagon ruins until the Brotherhood of Steel arrived. They finally get it up and running for the battle to take back Project Purity from the Enclave. And then blown up by a Kill Sat controlled by Enclave. They managed to rebuild it in Fallout 4 in order to destroy The Institute, but it can potentially be hacked and turn on the Brotherhood depending on who the player wants to side with.
  • Fallout: New Vegas has one hidden in plain sight: HELIOS One, a large solar power plant that's also linked up with a Kill Sat called Archimedes II. The Courier can decide whether to reactivate the connections to Archimedes II or strictly use it as it was originally designed, leaving said superweapon forgotten.
• These appear in Distant Worlds as discoverable technology from ruins in any planet that is not a gas giant and they can be reverse-engineered as usable equipment for your warships. Access to such weapons can greatly shift the balance of power among races as you now have a fearsome One-Hit Kill weapon to easily win your battles.
• Some stuff of Precursor origin in Star Control II, most notably the Sa-Matra battleship - that curb-stomped the Alliance fleet at the end of the war in the hands of the Ur-Quan- and the Utwig Bomb, able to destroy a planet. You must use the latter to destroy the former.
• The Old Sentinel from Battleborn is a legendary Artifact of Doom based on Ekkunar for at least a thousand years, probably zillions according to Mellka. Originally thought to be just the stuff of stories, Rendain was able to find its location and decided to acquire it. The objective of The Sentinel mission is thus for the Battleborn to destroy the titular sentinel per the Eldrid Observatory's instructions as it was deemed better that it be dead than fall into Rendain's hands much to Mellka's dismay as she sees the Sentinel as a sort of childhood hero from the stories she heard about it.
• The Elder Scrolls:
  • Daggerfall has the Numidium, a Reality Warping Humongous Mecha of Dwemer origin. In the series' backstory, Emperor Tiber Septim was given the Numidium by the Tribunal of Morrowind in exchange for special privileges as a Voluntary Vassal. Septim used it to great effect in conquering the rest of Tamriel. After Septim began using the Numidium in ways not intended, one of his agents who helped him gain control over it destroys it, sending its power source outside of the mortal realm. Daggerfall's main quest has the player coming into possession of the control rod and power source for the reconstructed Numidium, and then deciding which of several competing factions gets to have the weapon.
  • Morrowind has Physical God Big Bad Dagoth Ur discovering the blueprints for the Numidium and using them to construct his own mecha, Akulakhan, to be powered by the still-beating heart of the "dead" creator god Lorkhan. (Which is what the Dwemer originally planned to use to power the Numidium.)
  • In general for the series, any Dwemer technology can qualify. They were by far the most scientifically advanced race on Nirn and learned how to bend the laws of nature and physics to make their creations last. Even thousands of years after their disappearance (believed to be related to their use of the aforementioned Heart of Lorkhan), intrepid scholars can use the abandoned Dwemer tech to accomplish feats no one else can match. Perhaps most impressively, the Dwemer were able to create a machine capable of reading the Elder Scrolls without subjecting the user to the nasty side effects of blindness and madness.
• A Very Long Rope to the Top of the Sky: The God's Eye, when used as a city-destroying weapon, was lost in an area that was so sacred, it wasn't explored until the heroes found it. Or just how to make it was forgotten, given that the components to make another one can be found in other places. It's just that a complete one is in that lost location.
• Heaven's Fury in Ancient Empires II. The Big Bad gains access to it in the final mission and uses it to bombard your forces. It appears as a ball of light that falls from the sky and does high damage, thankfully only to a single unit at a time.
• In The Legend of Zelda: Breath of the Wild, the Divine Beasts and Guardians are advanced superweapons that were used to defeat Ganon thousands of years ago. They were lost until a hundred years ago the king of Hyrule had them excavated due to a prediction of Ganon's imminent return. Unfortunately for everyone involved, Ganon had learned how to gain control over them...

Web Comics

• Girl Genius: Subverted when the legendary Storm King returns from the dead bearing his Legendary Weapon, only to have Simon Voltaire No-Sell its effects. Voltaire points out that he's one of the intellectual descendents of the Spark who created the weapon in the first place, and has the benefit of two hundred years spent studying the operating principles of the weapon, improving on the design, and developing countermeasures.
• Before the events of Tower of God, the Irregular Enruy visited the 43rd floor of the Tower and left behind a "Thorn" (which looked something like a giant red pointy rock) that was meant as a weapon to kill Jahad, the King of the Tower, who has Complete Immortality otherwise. Later, a lot of people put a lot of effort into finding the pieces of that Thorn so they can be put together again. It's been shown that possessing just one of those pieces gives the possessor the ability to enter Super Mode.

Web Original

• The Iormunean Imperial Templar's blessed weapons from Open Blue are divine armaments enchanted with various elements and powers. Compared to the weapons of the present timeline, they're definitely superweapons.

Western Animation

• Surprisingly (And hilariously) subverted in Ben 10 when Enoch searched for an ancient Mayan sword. Grandpa Max had been so distracted by getting it first and keeping it from the wrong hands, it almost killed his grandchildren. With the final opportunity, he gave up the sword in exchange for saving Ben and Gwen's lives. Of course that means Enoch now has the sword... which turns to dust soon after he picks it up.
  Max: (Laughs after the sword turns to dust) Guess that's what happens when the world's most powerful sword is over 5,000 years old.
  • The Sword of Ascalon in Ben 10: Ultimate Alien fares better probably because it was made by alien technology and was used to cut out and contain the heart of an Eldritch Abomination a thousand years before the series. Unfortunately, it (and the heart of said abomination) didn't stay lost.
• LEGO Star Wars: The Freemaker Adventures: The Kyber Saber, a lightsaber with a blade made entirely out of Kyber crystals (which are ordinarily contained within the hilt of a normal lightsaber and determine the blade's color). When the saber's creator saw that the blade was powerful enough to destroy entire planets with little difficulty, he broke it into pieces and scattered them across the galaxy. The show's first season is about Rowan using his limited connection to the Force to find the pieces of the saber before The Empire.

Real Life

• In the early days of World War II, Britain was in dire need of large caliber heavy artillery to defend against a cross channel invasion. However, because the production lines to make such weapons had been dismantled after World War I, new weapons of the same type could take years to produce from scratch. Records indicated that a number of large railway guns had in fact returned home from WWI, but, despite their size, had been "lost" in the intervening years. In November 1939, a Lt Colonel was sent on a quest to locate the guns and after months of fruitless searching he noticed a large disused railway shed at a Royal Ordinance depot. Forcing the doors open he discovered no fewer than 20 9.2" railway guns and 12" railway howitzers along with three additional 14" named railway guns (Boche-Buster, Scene-Shifter and Gladiator). These were all promptly reconditioned and put back into service.
  • Another story has it that a Royal Ordinance surveyor was inspecting a railroad line for suitable firing locations when he discovered another shed with a perfectly maintained 9.2" railway gun inside. A short while later an older man showed up and explained that he had been collecting a small stipend to look after the gun for the last 20 years.
• During the Cold War, the United States had 6 Broken Arrow incidents in which nuclear weapons were lost and never recovered. Most of these incidents occurred in the ocean due to nuclear bombers crashing or accidents aboard carrier ships. One nuclear bomb was lost just off the coast of Georgia. Finally, a nuclear bomb (which was highly likely to have been partially armed on impact) is buried in a field in Goldsboro, North Carolina, the site of yet another nuclear bomber crash. Unable to locate the device, the government purchased the land to prevent people from digging around it.
• During the Cold War, the CIA set up a remote listening post powered by a plutonium energy device on the Indian mountain of Nanda Devi, in an operation known as Operation Hat. The plutonium energy device was eventually lost, potentially being buried in the ice of the mountain; if it were to melt its way out of said ice and contaminate the Ganges River, the source of much of India's water, it could lead to a massive environmental catastrophe.

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