"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."
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 cousins the Ancestral Weapon and Forgotten Superweapon, the Lost Superweapon is lost, and not just down the back of the sofa with some loose change and badly crumpled hidden back issues of Playbeing. (For the latter, see Superweapon Surprise.)
Lost Superweapons are generally a type of Plot Coupon and found in fantasy novels and video games. If the Lost Superweapon has become a notable part of the landscape, then it is a Weaponized Landmark.
- 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 Hell found were ancient, outdated, mountain sized piles of scrap.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, as part of its Myth Arc, the existence of three super weapons, Pluton, Uranus, and Poseidon. They are so rare, powerful, and difficult to obtain that one villain tries to conquer an entire country just to facilitate finding one. One is apparently a battleship of some kind, and another is the Mermaid Princess' ability to command the Sea Kings.
- The God Warriors of Nausicaa of the Valley of the Wind.
- The Saint's Cradle of Magical Girl Lyrical Nanoha StrikerS.
- The Ark of the Covenant in Raiders of the Lost Ark is a Grade A Lost Superweapon.
- In Mad Max: Beyond Thunderdome, Max wants to intimidate one of the tribal teenagers into staying in the camp. He snatches a decorated ceremonial spear from another tribe member, strips off its decorations, extracts the rifle that the Scavenger World kids had unwittingly used as a spear-shaft, and fires a warning shot. Not as ancient or as "super" as most examples of this trope, but it's a lot deadlier than their javelins, so it fits.
- Star Wars expanded universe novels have the entire solar system of Corellia is made of giant spaceships disguised as planets with the tiny station of Centerpoint being the control center. The 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.
- Other Star Wars examples include the Sun Crusher (which was forgotten because it was built in a remote Imperial wormhole facility that no one really knew about), 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).
- 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.
- Given the Technological decline, the propeller will prolly break on you and you'd end up running over a cliff.
- 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 Swartzchild 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 against the Ultimate Evil 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 Hitch Hikers Guide to The Galaxy, 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 millenia later had the Omnicidal people of Krikkit rebuild the bomb before planting it on Arthur Dent, who very narrowly avoided setting it off.
- 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.
- 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.
- 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.
- 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.
- Orichalcum is an ancient Atlantean superfuel/explosive in Indiana Jones: Fate of Atlantis.
- The titular Halos.
- 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. Egg...er, Robotnik'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.
- Guillo in Baten Kaitos Origins. It was abandoned by the Children of the Earth after the war of the gods, since they felt that a weapon that could kill a god wasn't a good thing to keep around.
- 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.
- 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.
- What did they make that sword out of, if it's turning to dust? Then again, 5000 years probably eliminates the possibility of mayan metal weapons anyway.
- The Sword of Ascanlon 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.