Downplayed with the demon blade Toukijin. It is so powerful it possesses its creator, kills him due to the sheer force of its power, and then continues to animate the corpse afterwards until Inuyasha hacks off the corpse's wrist to separate the sword from the body. Not even the story's Ultimate Blacksmith is capable of approaching it, causing the protagonists to warn Sesshoumaru that he'll be consumed by the sword if he touches it. Cue their absolute astonishment at Sesshoumaru's effortless victory over the sword's evil via willpower alone. Eventually, Sesshoumaru destroys the blade when the force of his compassion becomes too strong for the sword's hate to handle. Sesshoumaru is able to eventually replace it with a better sword.
Soul Eater: The Black Blood is shown to be this. It gives the user great power (the ability to control your blood, seal deadly wounds and synchronise more effectively) however it does come at a price. Overuse leads to drowning in the madness, a black gooey substance which can only be overcome by an exorcism wavelength. The madness can even manifest itself as an alternate ego within your own soul, as seen with Soul's Little Demon.:
It's common practice to design cards so powerful they are too dangerous to be used. They have to be locked up and kept out of the wrong hands to give the protagonist and company something to fight for.
The Wicked God cards of Yu-Gi-Oh! R were considered too dangerous to even be printed by the people who created the aforementioned cards of doom. Naturally, someone decides to print and use them anyways. Unsurprisingly, one of them brain-jacks him.
The orichalcum cards are forged by taking a piece of a green meteorite, the orihalcum, and fusing it with a blank card. The card creates a specialized field of play that that works in favor of certain strategies. Unfortunately, their supernatural powers capture the loser of the game and place him/her in a pocket dimension to be used for a demon ritual. The orichalcum itself is the artifact that started the series - the meteor that turned the citizens of Atlantis into monsters when it crash landed, and were captured and turned into summon spirits by the Egyptians.
The Millennium items around which the series is based are also dangerous. The Millenium Ring from the original series is the most notable example. While all of the Items (especially the Eye and the Rod) can be used for negative purposes (and tend to turn their owners into megalomaniacs or drive them insane), the Ring is the absolute worst, possessing the innocent Ryou Bakura and using him to trigger a plot that would have seen thousands of people dead, and history rewritten. Having the soul of a psychopathic tomb robberand a shard of a dark god's essence trapped inside of it will do that to an object.
Yu-Gi-Oh! GX features the Super Polymerization card in season 3. The unstoppable fusion card used by villains to fuse any monsters to win duels, fuse dimensions to threaten reality and used by Jaden to permanently fuse himself and the Big Bad Yubel to end the conflict between them.
The eponymous notebook from Death Note kills those whose names are written in it. This is slightly different from most of the other examples on the list, in that it doesn't appear to be sentient or corrupting all on its own — the danger comes entirely from the power it places in the hands of the user, and how he decides to use it. On the other hand, to quote Ryuk, "Don't think somebody who uses a Death Note can go to Heaven or Hell." What Ryuk doesn't say is that there is no afterlife — nobody is going to Heaven or Hell. He also mentions (in the very first episode) that the first human that picks up the Death Note will ultimately have their name written down by the Shinigami that dropped it. Sure enough, following Light's ultimate defeat in the final episode, Ryuk makes good on his promise and writes Light's name into his personal Death Note making it the first, and last time, Ryuk uses his own notebook in the series and finally closing the Kira case..
In the anime of Sands of Destruction, the "heroine" Morte carries around with her a little black sphere called the Destruct Code, which supposedly has the ability to destroy the world. However, she has no idea how to use it though it seems to react to main character Kyrie. Those who have played the game know that Kyrie himself is the actual Destruct Code. Here, he's a being that has existed since the dawn of the world, created for the specific purpose of destroying the world should the need arise. The little black sphere mentioned above was a device he used to store his memories; when he lost it 4 years prior he developed amnesia.
Digimon Adventure 02 features the Dark Spores. The good news: they make you faster and stronger, and provide genius intellect. The bad news: They turn you cold and sadistic. Worse news: their real purpose is to resurrect a seriously nasty baddie once enough of them have collected enough energy from those they've corrupted. Even worse news: they're imperfect copies of the real thing, so if they're not harvested, you die. But there is good news: I Just Saved A Bunch Of Money On My Car Insurance By Switching To Geico!
PS: Don't play with the Beast Spirits in Digimon Frontier, either. You can learn to control yourself while using 'em eventually, but that's only after an episode or two of wrecking everything in sight. If you're not one of The Chosen Ones, using 'em at all may be hazardous to your sanity.
There's also Guts' Berserker Armor, which removes a human being's natural limits by nulling pain and allows the user to keep fighting by temporarily mending broken bones, stitching together wounds, etc. It's very dangerous for the obvious reasons that your body has limits for a reason and bypassing them is bound to hurt you, but it also has the effect of bringing out the wearer's "inner beast" (in the Skull Knight's case, his familiar skull motif, in Guts' case, "The Beast", his Hell Hound evil side), turning him into a raging monster incapable of distinguishing friend from foe. After using it just once, Guts got a patch of white hair, became partially colorblind, and lost some of his sense of taste. Constant use of it might have reduced the Skull Knight to his current ghastly state.
The Book of Darkness from Magical Girl Lyrical Nanoha, which grants ultimate power to its user upon filling its 666 pages. Oh, and it takes over said user once said pages are filled and goes on an omnicidal rampage until it burns itself out together with said user, whereupon it resurfaces somewhere else to snooker another mage. The guardians that accompany it never mention that part for some reason. If you're Genre Savvy enough to not use it, it will just eat your life force instead. It's an interesting case, in that the only reason it's an Artifact of Doom is that it's malfunctioning. As it originally was, it was a harmless book meant to store knowledge of magic from all over the universe.
Fans also like to joke that Raising Heart is one of these. Especially in doujins, she and Nanoha are prone to unleashing big pink beams of death and destruction love and friendship anytime, anywhere, on anybody.
The Mesoamerican stone mask from JoJo's Bizarre Adventure is the main cause for most events of the series, especially the bad ones, due to its ability to turn the wearer into a vampire when splashed with blood. Later, the Stand Arrows fill a similar role.
Ann Cassandra: The Cassandra Mask. The mask's power lets its user warp the future to cause more disasters in exchange for becoming the mask's puppet and eventually dying. The mask then compels the nearest person to pick it up and use it.
The Dark Bring in Rave Master, which grant the user different powers while slowly corrupting them. Special mention goes to the Sinclaire, which are especially corruptive.
The library of 103,000 grimoires in Index's brain counts. Not only do the grimoires themselves contain spells of incredible destructive power, the knowledge itself is dangerous. When one mage tried to absorb just one of the books while trying to obtain a healing spell to save a girl he loved from a curse, he nearly suffered a fatal aneurysm. The mage then wonders just what Index is considering that she can store the entire library in her mind without any negative side effects.
Dáinsleif would probably also count since it will trigger Ragnarok if it is fully unsheathed. Fortunately it's wielder can't bring herself to do so and it is destroyed shortly afterwards. In fact this particular artifact of doom is so doomy that its first use seen is to cause fatal heart attacks just by threatening to use it!
Neon Genesis Evangelion has the "Lance of Longinus", a long, pronged artifact which grants its wielder (who has to be absolutely GIGANTIC to use it, by the way) absolute godly power. It plays a crucial role in both the Second and Third Impacts. The Lance is interesting in that it is not sentient, nor is its wielder, Adam,truly "evil"; it is only an Artifact of Doom from a human perspective, being as it will destroy us all if it falls into the wrong hands.
Classified Information suggests that the Lance actually is sentient, and comes in a set with a Seed of Life (i.e. both Adam and Lilith had one, but Lilith lost hers). It exists as the ultimate security device, but only does anything if something goes horribly wrong (such as two Seeds landing on the same planet).
Nabari No Ou - The "Book of the Knowledge of All Living Things" is essentially this though it doesn't necessarily corrupt the holder himself.
Da Capo - the Giant Sakura Tree; though it is explicitly stated that it only fulfills one's fervently wished for desires, for some reason, it always end up working towards unimaginably evil ends (in the second season, it defeats the Power of Love). May be linked to its tendency to fulfill unconscious wishes even when this goes against the conscious desires of the user.
Sakura states in the second season that the tree's purpose of granting wishes may be inherently damaging as it disrupts the struggle which is central to human life, thereby disrupting the process of human life itself. Essentially, since people don't know what they want granting it to them will inevitably go awry.
The titular Turn A Gundam is revealed to be responsible for the Black History, a time when Earth's technology was destroyed, killing a great deal of Earth's population as well. Turn X is also capable of this scale of destruction. This news is disturbing to main character Loran, who has up to this point only used his Gundam to try stopping people from killing each other.
In Pokémon Special, the Red and Blue Orbs are this, as merely touching them can drive you insane, and holding them for too long will cause them to fuse to your body and become crazed puppets for Groudon and Kyogre. Only by training one's mind and spirit can prevent this.
Soul Gems in Puella Magi Madoka Magica are an odd variation on this. They hold tremendous power, but anyone who possesses one could easily become an Eldritch Abomination by using them too much, or by losing control of their negative emotions. The twist is that they're the heroes' Soul Jars, not the villains', and the artifacts themselves are not evil... they just have a tendency to amplify the evil (and the good) in their human hosts.
In The Circumstances Leading To Waltraute's Marriage, dwarf-forged tools and weapons tend to be cursed. Gods and Valkyries are too powerful to be affected, but anybody else who tries to use them will suffer misfortune and death. The dwarves tend to do this out of revenge for their customers threatening and/or cheating them. When Jack Elvan (who was unaware of the threat of cursed tools) pays upfront and is polite, they give him a curse-free tool.
The Black Scrolls in the Legend of the Five RingsCollectible Card Game and tabletop RPG are immensely powerful magical scrolls that corrupt any who study them. In fact anything (including people, places and objects) that has enough of the Shadowlands Taint does so, and various artifacts bear the Taint. These include the Bloodswords and the Anvil of Despair, just to name two.
The Mirari twists and corrupts those who seek its power in the post-Invasion world of Dominaria in the storyline. However, this is a subversion; it's revealed in the end that it was only meant to be a probe, but ended up spilling magical power into the world, the power inevitably corrupting the bearer.
Also, within the card game exists the Door to Nothingness artifact. Its ability costs a ridiculous amount of mana, but when activated, your opponent loses the entire game. (Just make sure they don't redirect the target.)
Worldslayer. "Whenever equipped creature [i.e. creature wielding the sword] deals combat damage to a player, destroy all permanents other than Worldslayer."
The Hedrons in Zendikar are powerful, valuable, and tend to be dangerous. Ironically, they were created to help imprison the Eldrazi, but the leaking power of the Eldrazi tainted them.
The Chain Veil. It's telling that Liliana Vess wants to get rid of it despite the artifact's immense power. Unfortunately for her, the Veil isn't done with her yet.
In the Marvel Universe, the Darkhold is a Tome of Eldritch Lore penned by Chthon (an Elder God turned demon lord) to serve as a foothold in Earth's dimension after his banishment from it. Anyone who uses it risks becoming enslaved to Chthon's purposes.
Possibly worse, the Resurrection Stone, which is Exactly What It Says on the Tin. It also invariably drives all who possess it or seek to possess it insane. The consciousness of the gem is malevolent and seeks to bring chaos to the universe while feeding on Man's desire for immortality. Ultimately, no mortal being can withstand such power. Entire civilizations have been destroyed by the madness it brings with it.
The Infinity Gemsprobably aren't inherently evil, but they are definitely trouble. The entire universe has been threatened more than once by a madman wielding the Gems.
Satirized in Nodwick by "This One Ring", which is a One Ring parody that inspired an epic Lord of the Rings-esque plot based on hype alone. It has no actual powers, but only Nodwick realizes this and no-one else believes him. By the end of the story, history repeats itself when Nodwick bribes off the story's Gollum-equivalent with "this one rock". Yeah, it's just a rock. Cut to the Distant Finale...
The print comic also features a straight example in the Gauntlet of Supremacy. It renders its wielder immune to harm, fires powerful energy blasts, and gives the wielder dominion over all living beings near them. Unfortunately, it was forged by a God of Evil and a God of War working together, and drives its wielder to conquer the world and kill anyone who opposes them. Only said God of Evil can control it.
In the DCU, the Heart of Darkness is a black crystal that can grant its host fearsome mystical powers. The cost? Said host almost always becomes a flesh puppet to the evil spirit within the diamond, often referred to as "Eclipso".
The only time Eclipso was ever contained, the captor used special tattoos all over his body to turn himself into a living prison. Unfortunately, those were broken by an accidental slice from his lover Nemesis, and the freed Eclipso ended up killing both of them.
The Tactigon from Avengers: The Initiative might go here. It's a shapeshifting alien weapon that can become whatever its host wants or needs. It's choosy, too; it won't work for just anybody, but it has an unfortunate tendency to pick hosts that are... troubled. Its first known host was a suicidal girl who at least tried to use the Tactigon for good, but its second host was out and out Ax-Crazy.
Although it's more of a Tome of Eldritch Lore in the Evil Dead movies, the Necronomicon develops into this in the comic book Army of Darkness spinoff, possessing a malevolent sentience, corrupting the people who stumble upon it for its own purposes, and generally trying its best to get rid of the hero once and for all. Oddly enough, as the comic books developed the Necronomicon into an Artifact of Doom, its Tome of Eldritch Lore traits seemed to diminish accordingly: more often than not, the comic book version of the Necronomicon simply uses its powers as it or its owner sees fit, with no spell recitation involved. This might've been a Pragmatic Adaptation for the comic book's episodic format, since very few people in the Evil Dead universe are qualified to translate and read the book's ancient language aloud.
The title artifact of The Mask grants its wearer Nigh-Invulnerability and reality warping powers, but also loosens their inhibitions until eventually they become a cackling Ax-Crazy mass-murderer. It's also addictive, and can't be removed by anyone other than the person wearing it (unless the wearer himself allows it).
A clever (probably originally Italian) Donald Duck story centered around a mysterious item from outer space that did absolutely nothing, but was still more an Artifact of Doom than a MacGuffin. It was so absolutely and completely useless anything done with it was automatically a waste of time and amounted to nothing. It was in the possession of Scrooge McDuck first, so he naturally tried to make money out of it, but his every attempt merely broke even, until he managed to sell it to Rockerduck (at zero profit). As time went on, the sheer uselessness of the item made it hold a peculiar fascination to people, and news of it apparently spread globally. Everyone was in fact so affected by the uselessness that they began to turn apathetic and think nothing was worth doing because it was useless, or were inspired to start doing completely useless things themselves. A researcher then came to the conclusion that the item could cause The End of the World as We Know It unless it was launched back into space to remove its effect on the collective psyche. But when they did this, the story subverted its own premise, because the item saved the entire planet; it was picked up by an alien armada of doom, whose leader consequently decided attacking the Earth would be pointless, and decided not to bother. Perhaps a True Neutral equivalent of the default evil Artifact of Doom.
The Winslowe in Buck Godot: Zap Gun for Hire is something of a subversion in that it is alive, slightly mobile, slightly intelligent (actually quite intelligent), and to all appearances not the least bit malevolent or proactive in any way. That doesn't change the fact that any time it pops up, half the known universe goes violently crazy with avarice to possess it, because they're convinced it is the most important object/being in all of Creation.
Any of the various Green Lantern Corps rings could become an Artifact of Doom under the right circumstances. The Orange Lantern ring curses its owner with ever-lasting greed and hunger. The Red Lantern ring causes heart stoppage and uncontrollable rage, and you can't take it off without it killing you. The Black Rings bring the dead back as undead Black Lanterns that crave hearts.
The Star Brand from The New Universe is exactly like this. A limitless power only held back by one's imagination, it can only be used by living things. The first time someone tried to place it into a inanimate object to get rid of the power, it initiated the White Event, the world's biggest Superpower Lottery. The second time, it vaporizedPittsburgh! Even worse, even if you do get rid of it, you're keeping a portion of the power that will recharge itself back to full. It's so dangerous that, when the New Universe Earth was transported to the mainstream Marvel Universe, the Living Tribunal erected an impenetrable barrier so it won't contaminate the rest of the universe with its power.
Trinity War has Pandora's Box, which contained the Seven Deadly Sins of Man and can also re-contain them. It can only be opened by those with the strongest or darkest heart. Those that aren't get corrupted by it when they hold it. And in the finale, it turns out to be an advanced piece of technology that opens a doorway to Earth 3, the birthplace of evil, and allows the Crime Syndicate to arrive on the Prime Earth.
The Sandman: when he is trapped in the opening chapter Dream has his mask, ruby and pouch of dream sand stolen. While the mask doesn't do anything (the demon who gets it knows how dangerous and powerful it is) the pouch of sand falls into the hands of a drug addict who uses it to get a high, only for it to start turning her home into a nightmare landscape. The ruby on the other hand is used by a mad scientist who starts using its powers to take over the world and is stopped by the Justice League. The items themselves aren't evil, just really powerful because Dream poured his power into them to make them what they were.
In Child Of The Storm the Darkhold is very definitely this - kept in the vaults of a castle guarded by the most powerful technology, magic and soldiers that can be found, it has... a reputation. And it proves its reputation when a spell from within it allows the Ax-Crazy Gravemoss to create monsters that Odin specifically exterminated and had all knowledge of destroyed. But the Darkhold cannot be destroyed. And it never forgets...
The Chitauri sceptre is treated as one. No one wants anything that has mind altering properties and that Thanos has had contact with in anywhere but the strongest vaults in Asgard.
The Immortal Game has the Sliver of Darkness, which was responsible for Princess Luna's transformation into Nightmare Moon, and more importantly to the story, Twilight Sparkle's transformation into Nihilus.
In With Strings Attached we have Blackfire, the Hunter's BFS, even though the Hunter doesn't think it's evil. He is disabused of that notion eventually.
Baumann Revenge: The All Stars Staff is the one responsible for giving Mr. Baumann the desire to get rid of Ben Tennyson. Turns out that it didn't follow Baumann's desires, and it has Undying Loyalty to its one true master, DX-4. It has Nigh-Invulnerability. When Verdona used her magic to damage it, it wasn't damaged. Black Hole was not able to damage it, because it was made from an unbreakable material despite his power. In the end, the only way to destroy it was to trick it into turning into its One-Winged Angel form and destroying the dragon inside it.
A Future of Friendship, A History of Hate has the Tear of Covet, the gem that Miserain gives Scootaloo to enable her wish to become an adult. While it does as advertised, it turns out it was feeding off the despair she felt when her wishes blew up in her face to power a creature called a woebeghoul contained within it, and when she enters a Heroic BSOD, the ghoul breaks free and absorbs her before attacking Ponyville.
Shadows Awakening: The Dark Treasures, formerly the Imperial Regalia of Japan — were corrupted into this by the Dark Champion of the Shadowkhan long ago. In addition to the fact that combined they can open the Forge of Shadows (the place where the Shadowkhan were originally created), they also have corrupting influences of their own:
The Kusanagi sword can possess the person using it and turn them into a Blood Knight berserker.
The Mirror of Despair puts Tohru in a coma when he looks into it, trapping him in a vision of a Bad Future until Uncle is able to wake him up.
The Jewel can bring a person's self-doubts and darkest thoughts to life as shadow doppelgangers to torment them. They can't cause physical harm, but the emotional torment is a useful tool in battle.
Fallen King has the Millennium Eye and Ring, but the Millennium Puzzle is the one most touched upon. Being near its pieces lets those in proximity summon monsters, and Pegasus plans to use it to rewrite reality.
Zenith has The Pillar of the Sun. 1,000 years ago, it was stolen by Sombra as a weapon to kill Celestia. Unfortunately, 1,000 years later, it ended up getting Twilight, instead.
The World of the Creatures features the Biolangra - a powerful magical object that grants the person who wields it the power to either unite or destroy all life in the eponymous world.
The Book of Shadows from Ojamajo Doremi Rise Of The Shadows is a subversion. Even though it has everything the Big Bad needs to complete her plans with (in addition to telling the history of the Shadows), it can also be used to defeat the Shadows once and for all.
In the Facing The Future Series, we have the Scepter of Fay, which makes anyone wielding an Amulet of Aragon all powerful.
In Romance and the Fate of Equestria, Trixie comes to Twilight asking for information on the Ears of the Beast, a magical artifact she's found. They turn out to be the actual fossilized ears of a chopped-up Eldritch Abomination. The artifact is wielded by cutting off one's own ears and replacing them with those of the Beast, granting immortality and immense magical power but an obsession with putting the Beast back together. Later on, the story's Terrible Trio are revealed to be wielding other pieces of the Beast.
In Sunset Of Time, the Dark Regalia are ancient relics that amplify a pony's powers, and when all three are worn together it turns them into an alicorn. The catch is they corrupt the user's mind, driving them insane and evil, and are powered by dark magic. And the transformation into an alicorn as one assembles the set is pure Body Horror.
Films — Animation
Maleficent's spinning wheel from Sleeping Beauty. The interesting thing here is that any spinning wheel could have fulfilled the curse instead of one particular evil/powerful one.
The Black Cauldron from... The Black Cauldron is ancient and can create an army of undead.
Films — Live-Action
The One Ring from The Lord of the Rings is the Trope Codifier and this page's image. It contains the bulk of Sauron's power and will corrupt whoever wears it (except for Tom).
The infamous videotape in The Ring will kill whoever watches it.
The Lament Configuration (the puzzle box) in Hellraiser films, a key to open a portal to the hellish realm of the Cenobites.
The gun from Juice. The moment Bishop uses it, he is unable to stop using it even on his friends.
The Coke Bottle, from The Gods Must Be Crazy. Although it's just a normal, ordinary soda bottle, its effect on a tribe of bushmen due to its usefulness and its rarity causes so much trouble (culminating in one of their number using it as a weapon to hurt another) that they decide it's an evil thing, which must be thrown off the edge of the Earth.
The cellar in The Cabin in the Woodsis filled with Artifacts of Doom with the intention of getting the victims to play with the objects and doom themselves.
In The Brass Teapot the titular artifactďż˝s power latches unto the slightest trace of evil in a personďż˝s soul and amplifies it until the person is utterly corrupted by greed. It has left a trail of death and destruction across the entire world in the two millennia of its existence.
The Darklord weapons and the Death Staff are examples of evil weapons that have gameplay penalties when used in battle.
Story-wise, the worst artifacts are the Doomstones. The Doomstones are essentially crystallized Black Magic created by a powerful demon that eventually corrupts and kills anyone who uses them that isn't already a being of pure evil. Meaning that the strongest antagonists can use them with impunity; but Lone Wolf collapses as soon as he gets near one. The Doomstone of Darke featured in Book 16 The Darke Crusade deserves a special mention here. In the end, it turns out to be the REAL Big Bad of the book, having made the Disc One Final Boss its frail, near-undead puppet.
A rather weird example is the Moonstone, a GOOD Artifact of Doom: crops grow better, children are born healthier, summers are longer... but it threatens to destroy the natural equilibrium of Magnamund.
The quintessential example is The One Ring from Tolkien's The Lord of the Rings. The Ring grants power proportional to that of the wielder, so the effect on a mere hobbit is minimal (it just helps them "disappear" and makes them live forever), but in the hands of an elven mage or a demigod like Gandalf, it's a world-breaking artifact. The downside is: it contains the spirit of its maker, the Dark Lord Sauron (aka the Necromancer), so it will eventually corrupt anyone who wears it, or owns it, or even sees it. Also, it's virtually indestructible, and the quest to destroy it takes about three-quarters of the plot.
The palantíri, also from The Lord of the Rings, are basically just sort of far-seeing crystal balls, but they are functionally dooming at the time of the story, because Sauron got hold of one and used it to psychically attack anyone who uses the others. (Victims include Saruman, Denethor and Pippin.) They also seem to exert a strong fascination and temptation to use them for some reason or other, but maybe that's just hobbit curiosity. Aragorn breaks the spell and wrests the palantír for his own purposes right after he spooks Sauron by showing him, reforged, the blade that cost him the ring and a finger
The Silmarils (of The Silmarillion) aren't precisely doomy, but they seem to have a dooming effect on everyone around them, because everybody who sees one (or even hears about it) covets them. Including Morgoth, who wears them in his crown even though their holiness burns him. Also, Mandos lays a Doom on the Noldor who seek the Silmarils, and anyone who gets involved with them, including the Sindar, the Dwarves and Men.
In the John Silke series of Death Dealer books (which are based on the painting by Frank Frazetta) the main character is given a helmet possessed by the god of death, which makes him a nigh-invincible warrior. On the flip side, it will put Gath (the name given to the death dealer) through slowly increasing discomfort, pain, and finally torture. The helmet can only be removed by an innocent young woman, and final love interest, named Robin Lakehair.
The first two books in Lloyd Alexander's Chronicles of Prydain series had the Black Cauldron, based on a Welsh myth, used by Big Bad Arawn to create his army of the undead. (The Fates imply that the Cauldron once had other, more benign uses, but Arawn ruined the thing while he was "renting" it.) To destroy it, Someone Has to Die, and it can apparently corrupt former good guys who covet its powers. The Disney Animated Canon made a very loose adaptation simply titled The Black Cauldron.
Somewhat subverted in Excession by Iain M. Banks, in which the Excession is an object which does absolutely nothing, but almost causes a galaxy-spanning war over who gets to say they own it.
The Piggy from William Sleator's Interstellar Pig also does nothing, but causes a lot of trouble. The aliens chasing it believe that, when an unknown timer runs out, only the planet with the Piggy will be spared from destruction. But the Piggy itself later tells the human protagonist that it has the "hiccups" and will actually only destroy whatever world it's on during its next hiccup. The hero soon realizes these are both lies to keep "the game" going: the Piggy's real purpose is to study each alien species, and the story of the game exists solely to manipulate everyone into alternately chasing it and tossing it like a hot potato.
In Steven Brust's Dragaera books, Morganti weapons have a cold, low-level intelligence that hungers to consume souls. The blades are so awful that they even unsettle their bearer. However, the most powerful Morganti weapons are called Great Weapons, and have a more developed intelligence that can be controlled, leading to a symbiotic relationship.
The Blackened Denarii from The Dresden Files. Just touching a coin is enough to invite the fallen angel bound to it into your mind, where they will toy with your perceptions, offer you power, and eventually turn you into their flesh puppet. Mordite (a.k.a. "deathstone") is worse. Any entity short of an Eldritch Abomination will suffer Critical Existence Failure simply by being near it.
The Illearth Stone from the Chronicles of Thomas Covenant is pure evil and extremely powerful. Even shards cut from it are potent magic items that can corrupt people. Additionally, if the Illearth Stone or a shard of it is in one place for long, its evil anti-nature aura will kill off all the plants in a large radius around it.
Things like this also turn up in his Nightside novels, but in weirder forms (e.g. the Speaking Gun).
In P. C. Hodgell's Chronicles of the Kencyrath, the Ivory Knife and the Book Bound in Pale Leather are this and yet not, in that they're given to the Kencyr by their God, and will be used by the three avatars of God, the Tyr-ridan. The Ivory Knife is the "very tooth of death", a pinprick from which is fatal, which rots and kills anything it touches. Heroine Jame keeps it in her boot sheath for the longest time.
The short story "The Monkeys Paw" by W.W. Jacobs. The monkey's paw grants the user's wishes, but at a tremendous price. "It had a spell put on it by an old fakir, a very holy man. He wanted to show that fate ruled people's lives, and that those who interfered with it did so to their sorrow." The thing was created purely to cause suffering. It's pure evil.
The Wheel of Time has a city that acts like this. Shadar Logoth will quickly corrupt anyone who stays too long. This isn't much of a problem when you consider that people who enter will quickly get killed by Mashadar, an evil cloud that hangs over the city. Mat Cauthon picks up a dagger on his stay there, and this acts the same way. He quickly succumbs to hating people, and is nearly killed by the taint of the dagger before he is finally separated and healed of the taint. However, Rand eventually finds a way to use the city against the Big Bad without being corrupted by it, namely by making its power and the city's cancel each other out, albeit with the side effect of erasing the city and several kilometers of earth beneath it from existence.
Stephen King's The Dark Tower depicts two of a set of thirteen Artifacts Of Doom — the Wizard's Rainbow, a scattered set of color-coordinated crystal balls that inspire a covetous "my precious..." instinct. The pink one appears to cause addiction to Reality TV. But the Doomiest of them all, Black Thirteen, instead inspires a mixture of terror and murder-suicides, and is implied to act as a sort of Weirdness Magnet for disaster when Jake and Father Callahan unknowingly decide to stash it in a subway locker beneath the World Trade Center in June 1999.
Black Thirteen's doominess is a bit of an Informed Attribute, however, as the protagonists are able to use it to get all sorts of plot-relevant errands done with few side effects beyond the occasional creepy voice in the head / hallucinatory creepy music.
In William King's Warhammer 40,000: Space Wolf novel Grey Hunter, Ragnor and other Space Marines encounter an artifact which makes vast promises to them. Ragnor only breaks free when it tells him he has to kneel to the Ruinous Power to get it. And the others don't break free on their own; he has to help them.
May or may not be averted in C. S. Lewis' The Magician's Nephew, as the inscription over the enchanted bell only claims it'll drive you mad if you refrain from striking it. Even if it couldn't really cause insanity, ringing the bell awakened Jadis and introduced evil to Narnia, which is "doom" in a way.
That tome of ineffable horrors, the Necronomicon originating in the works of HP Lovecraft, though this is largely the result of being heavily Flanderized; a major percentage of the Lovecraft's protagonists read the book without becoming more than mildly neurotic. Breakdowns only tend to happen when what they've learned from the book seems to coincide with their recent experiences.
Played straight with the original Necronomicon (only, any other copies are just books) in German author Wolfgang Hohlbein's Hexer stories, which is actively malevolent, extremely unsafe to read, and tends to draw supernatural evil to itself partly through its own power and partly because it's secretly one of the Seals of Power that keep theGreat Old Onesin their respective prisons after their defeat by the Elder Gods.
In China Miéville's The Scar, Silas steals a statue from the grindylow which grants him mysterious powers, yet has the unfortunate side effect of slowly turning him into a fish-person.
Stormbringer, the black blade, in the Elric novels, forces Elric to kill everyone he loves, brings about The End of the World as We Know It, and ultimately survives the destruction and re-creation of the universe to spread its evil anew.
Terry Pratchett created a device called the Gonne ie. the world's first gun in Men at Arms. Anyone (almost) who so much as picks up the Gonne will think it "talks" to them; they begin to consider killing someone immediately. On the Disc, sometimes just being powerful or unique is enough to make something borderline magical, and the Gonne was both. What the Gonne feared most, though, was not destruction but replication.
In the Discworld novel Soul Music, a primordial guitar bought at a little mystical shop takes control of an aspiring musician and his band mates. The guitar isn't exactly evil, but it is selfish, destructive, and intent on making sure "The Band With Rocks In" dies young and goes out in a blaze of glory, whether they want to or not, in order to popularize its type of music.
Crenshinibon, the Crystal Shard, in R. A. Salvatore's Icewind Dale Trilogy, is considered by many readers to be an homage to One Ring. It's a sapient artifact forged from the souls of several liches, capable of constructing crystal towers that can focus sunlight into beams, and corrupts the wielder.
The lore states that Crenshinibon was specifically created as a giant middle finger to the 'good' races as it was powered by the symbol of all that was good - Sunlight. The liches apparently had something of a sense of humour.
The Horcruxes are sort of like the One Ring; they primarily function as Soul Jars for Voldemort, but can exert a corrupting influence to defend themselves. Never mind that the creation of them is an act of evil; it requires the wizard to commit murder as part of the ritual.
Not exactly doomy but definitely addictive is the Mirror of Erised in the first book. It shows you your greatest desire, but it is just an illusion. (In the movie Harry is shown sitting transfixed in front of it.)
The Elder Wand prior to coming into the possession of Dumbledore and later Harry would also qualify. It is the most powerful wand ever created so its users typically become drunk with power and knifed when they're sleeping.
Brandon Sanderson's Warbreaker features Nightblood, a sentient sword created for the purpose of slaying evil — except being a sword, it has no real idea what evil is, and as such continually goads its wielder to try killing everyone in sight just to be on the safe side. Also a Deadpan Snarker.
Despite not having any meaningful understanding of what evil is, Nightblood fulfills its purpose fairly well. Anyone with evil intent will feel compelled to pick it up, and will soon be involuntarily killing their partners in crime. It does, however, like to urge its proper owner to kill almost anyone so . . . yeah, we'll call that a design flaw.
In The Picture of Dorian Gray, the portrait itself. Dorian cannot age and stays young forever thanks to its power, but the painting turns more horrible and wretched with each evil act that Dorian performs, as a physical manifestation of his tainted soul. Dorian is drawn to and repulsed by it. By the end of the book, he has the painting locked in his attic, afraid to even look at it. In a fit of conscience, he decides to destroy it, unable to bear to look at his aged and wicked face from the canvas. He stabs it, but in doing so, actually kills himself. While the portrait isn't actually evil, it reflects the evil in Dorian.
The board games Jumanji and Zathura, while not inherently evil or malevolent, still often rain down misfortune and disaster on the players in the form of lions, homicidal big game hunters, meteor showers, and invading aliens, depending on which game you're playing. In both games, the only way to get rid of them is to finish the game (assuming it hasn't killed you first). However, even if the heroes do manage to finish and dispose of the game, more often than not it will just worm its way into the hands of another group of unfortunate saps.
In the Malazan Book of the Fallen book Midnight Tides, Rhulad Sengar's cursed sword (which he only grabbed to keep an enemy force from stealing it) grants him superhuman (super-Tiste?) strength and combat ability to match the greatest swordsman. And it even allows him to resurrect, as long as the sword remains in his hand, leaving him even stronger — hence harder to kill — than before. Unfortunately, the resurrection doesn't actually heal the wound that killed him (at least not immediately, or gently) and hurts, leaving Rhulad even less sane every time he's killed. And we've also seen, in the time between his death and resurrection, the Crippled God (the sword's creator and the series Big Bad) takes the opportunity to pound on Rhulad's soul before sending him back. Did we also mention the sword is cursed so that Rhulad can't let go of it, even if he wanted to?
The Bottle Imp has shades of this, in the Robert Louis Stevenson story of the same name. It will grant any material wish, but when its owner dies, he's doomed to go straight to hell. Ownership can be transferred to someone else but only if you follow the rules.
In Matthew Reilly's Six Sacred Stones and The Five Greatest Warriors, the sixth pillar gives the reward of "Power"; the ability to reshape the world according to its possessor's wishes. It also puts them through the ultimate version of power corrupts.
The NeverEnding Story: Subverted with Auryn, which removes memories from its user but can also change somebody's personality, as for The One Ring. The longer the Bearer has Auryn, the more he begins to be upset, irritable and angry. This is the case for Bastian, at last.
Questing Stones are reputed to be this in Septimus Heap. No Apprentice has ever returned after having been dispatched with one of them, until Septimus is given one and survives the Queste in Queste.
In Michael Flynn's The January Dancer, the Dancer, apparently. At one point two characters discuss whether one man who owned it had died when he disappeared — after all, all other owners have.
In the Book of Swords series, the twelve Swords forged by Vulcan all fit this to varying degrees, since they were forged for the ultimate purpose of spreading strife in the mortal world for the gods' amusement. The Swords' power and doominess is such that even the gods fall prey to them in the end. Tellingly, the only Sword that survives till the end of the series is Woundhealer, the only Sword that cannot harm anyone.
Adventure Hunters: The war golems found underneath a country town are so powerful and caused so much damage the last time they were used that they have become the local Nuclear Weapons Taboo and everyone who knows anything about them will insist they are a myth to discourage anyone from using them again.
The Prince's Crown, in A. L. Phillips's The Quest of the Unaligned, is this except under specific circumstances. To elaborate, anyone who touches the crown and is elementally aligned instantly dies unless an unaligned mage buffers them. A person who is not elementally aligned and touches the Crown will become a hoshek, a mage of pure evil. This can be averted by two people touching the crown at the same time, which instead allows one of them to bestow light magic on the other. The High Guardian of the Temple Of The Elements is capable of blessing the crown to negate these effects, allowing it to be used for the prince's coronation ritual.
The Sword of Martin from the Redwall series, is considered magic, but is good or bad depending on who wields it. Good characters can use it no problem and even gains master swordfighting skills while holding it. Yet if an evil character steals it and uses it for... well.. evil. They'll be cursed with misfortune and doom.
The "Unmaking Nexus" from Zeus Is Dead: A Monstrously Inconvenient Adventure, a living weapon that was commissioned by Zeus and constructed by The Fates during the final days of the first Titan War, is so powerful as to be able to kill an immortal god with a single sting. It can also just as easily kill the god who uses it, if they're not careful.
They have a strange habit of being in Sunnydale in Buffy the Vampire Slayer. The best one is the Hellmouth, but there's others as well.
In Angel, the evil law firm that Angel is given at the end of season four (not technically an inanimate artifact, but hey). It's a powerful weapon that will do whatever he commands, but it's always working to corrupt his thinking so that he will give it the commands it wants. The dare-to-use-it/get-rid-of-it argument keeps cropping up, too. Also worth noting: The law firm exists to do business with evil. If they just plain stop helping evil with it, and instead try to use it only as a weapon for good, the business will fail, and another law firm, beyond their control, will pop up to replace it.
Angel also had a more straightforward Artifact of Doom: the Shroud of Rahmon, a demonic shroud that drives anyone near it to go Ax-Crazy.
Way back in Mighty Morphin' Power Rangers, Rita armed the mind-controlled Tommy with the Sword of Darkness. The sword itself was not a corrupting influence; rather, its power was used to sustain Rita's spell. The sword's Zyuranger counterpart, the Sword of Hellfreide, drove the wielder crazy. (Or, in Burai's case, crazier)
Star Trek: Deep Space Nine: The Sword of Kahless appears to have the same effect on Worf and Kor, though this perception was unintended by the writers. As Kor mentions at one stage (whilst using the famous sword as a spit to cook his dinner), it's just a sword, not a holy relic. Nevertheless Worf and Kor each believe that their role in finding the long-lost bat'leth means they're destined to rule the Klingon Empire (Worf did become Chancellor and head of the Klingon Empire, albeit for a few minutes). After nearly killing each other they realize the sword will cause more problems than it will solve, and so they set it adrift in space. When the weapon is referenced in Star Trek Online, it is referenced as just a weapon that drew out people's dark sides because those who had it would have to deal with those who wanted it, thus going with the writers' intentions.
Masters of Horror: "John Carpenter's Cigarette Burns": Some guy, desperately in need to pay off his debts, goes in search for a long-lost film called La Fin absolue du monde on behalf of a private collector. Only shown publicly during its premiere (which resulted in a massacre), everyone that came into contact with it was driven to kill someone else or themselves.
Some are so bad that they have to be kept in a special room in the Warehouse and continually be covered in the purple goo they use to neutralize them. Even then it's best not to get too close. At least one artifact has the potential to cause an extinction-level event when used at a certain location (the Minoan Trident when used in the caldera of a supervolcano like Yellowstone, the eruption of which would end human civilization). The House of Commons Masonry is fueled by the rage of the entire Nazi war machine and can blow with the combined firepower of the London Blitz.
In Stargate SG-1, the sarcophagus is a device that creates eternal youth, and can even bring people back to life, but it's credited as the main reason the Goa'uld are as evil as they are. The Tok'ra don't use it, because "it steals the soul." In the episode "Need", Daniel Jackson got addicted to it, and eventually got to the point where he just didn't care about anybody else (which was really remarkable for him, at the time).
Also in Stargate SG-1 are the Ancients' Repository of Knowledge devices. Jack referred to them as Ancient head suckers because of the way they latch onto the recipient heads to download the knowledge to the recipients. These Repositories can download the entire knowledge bank of the Ancients into the mind of the user, however said information is too vast for the human mind to comprehend at our current evolutionary level. Therefore anyone exposed to the knowledge bank will have their minds completely taken over by it causing them to degrade and eventually shut down (die). Jack had his head sucked twice, and while he was able to build many advanced technologies, he was eventually unable to speak or comprehend anything other than the Ancient language and he nearly died- the second time he had to go into stasis to escape death.
The Objects in The Lost Room have the potential to be these, but they can also been used for good. The worst ones, though, are very dangerous, such as the Deck of Cards, which subjects you to terrible visions, and there's at least one combination of Objects with the ability to cause something unspeakably awful.
The Book of Pure Evil from the Canadian series Todd and the Book of Pure Evil is a Tome of Eldritch Lore that also functions as an Artifact of Doom. The book, which seems to be sentient and actively malevolent, appears to whoever has some great desire they wish to be fulfilled. In turn, the book (which can seemingly change its contents at will) provides a collection of spells that will grant that desire, though typically twist it in some way. The main character, Todd, was the first to use the book and it possessed him, causing him to nearly slaughter his entire school with The Power of Rock.
Babylon 5: The Thirdspace Gate opens the way for Eldritch Abominations to consume the universe. And they can make you want to open it when it's still closed.
The Soul Hunters (Well-Intentioned Extremist aliens who try to preserve the souls of especially wise beings at the moment of death]]) once created one of these by capturing the souls of an entire world at the moment of physical death...as they made a mass-transformation into energy beings. They were understandably upset about this. The Minbari observe "One soul can change the universe." What might a billion souls accomplish?
"Bad Day at Black Rock" deals with a rabbit's foot, taken from a rabbit captured in a graveyard at midnight during the full moon on Friday the 13th. It will grant its owner phenomenal good luck, until they lose it and will then have bad luck for the rest of their life (and after losing it, your luck will be so bad that "the rest of your life" won't be much longer).
The First Blade, the "jawbone of an ass" with which Cain slew Abel, is selectively like this. For most people it would be harmless but not too useful, as bone doesn't make the most durable weapons. If you have the Mark of Cain on you it's potentially powerful enough to kill the highest-ranking angels and demons. If Dean is any indication, it's also a very thirsty knife, and warps the user into feeding it repeatedly. And if you die while still in possession of it, it brings you back as a demon.
The song "Black Blade", by Blue Oyster Cult, is about a particularly nasty Artifact of Doom (see "Stormbringer", above; the song was written by Moorcock).
"Dissolve," by Jonathan Coulton, seems to be about one of these, but the lyrics are a little vague.
Myths & Religion
The Ark of the Covenant.
Greek Mythology: The Necklace of Harmonia, which was made by Hephaestus, for his wife Aphrodite's illegitimate daughter Harmonia. It allowed any woman that wore it to remain eternally young and beautiful, but was also cursed to bring disaster to its owners. It was worn by the queens and princesses of Thebes, most notably Jocasta, the wife/mother of Oedipus.
Norse Mythology: The ring of the dwarf Andvari in Prose Edda, from the tale of the Otter's Ransom. The ring had the power to increase gold, but when the gods robbed Andvari of the ring, he cursed it so it would cause the death of everyone that owned it. The further events suggest the curse of the ring is responsible for the death of Sigurd and the Niflungs.
The Ring of Gyges, a metaphor for corruption in Plato's The Republic. This ring merely turns the bearer invisible, as the One Ring had in The Hobbit, but Plato argued that the temptations the ring presents would ultimately corrupt anyone who chose to use it. Inevitably, theft, murder, and betrayal would follow, as these were the easiest and most obvious uses of the ring. Ultimately, the use of the ring proves so addictive that its bearer cannot part with it, and can think of nothing else but his jealousy of keeping it.
The Sword of Kullervo in The Kalevala, which in the end talks to Kullervo and is willing to help him committing suicide, enjoying drinking his guilty blood as well as it has drunk many an innocent blood.
There is a Polynesian fairy tale about a bottle that contains a demon that grants wishes to whoever owns it. The bottle cannot be lost, stolen or given to somebody else- if you want to get rid of it, you have to sell it, and you must sell it for less that you paid for it. This means that eventually the bottle becomes worthless and cannot be resold, however, if you die while owning the bottle, the demon gets your soul and you go to Hell no matter how good you were in life. Eventually it becomes worth so little it can only be resold one more time and owned by an evil sailor who decides that he's probably going to Hell anyway, so he might as well keep it and live his life in luxury.
In a Polish fairy tale, the fern flower will grant any wish, as long as it's only for yourself and you never share the benefits with anyone. If you are charitable even once, everything you wished for is taken back, and the flower disappears.
On a slightly less grand scale than the Blackstone Fortresses, there are a number of brand new ones introduced in the Warhammer 40,000 RPGs from FFG: the Halo Devices. Mysterious, but probably non-human in origin, these things can make the bearer immortal, but you wind up unsane and inhuman. On the upside, that which does not kill you makes you stronger, and that which does kill you doesn't make you dead. You simply end up with a mind completely unlike any human, including the insane worshippers of the Chaos Gods, and a body that slowly mutates into a vaguely insectoid monstrous form. And it doesn't work if you are psychic, or a Chaos worshipper. And "killing" the bearer, just hurries it along. Needless to say, these are rare, highly illegal, and are worth more than star systems.
A particularly notable daemon blade is the Kinebrach Anathame, which directly lead to the Horus Heresy and creation of the Chaos Space Marines.
The Sword of Khaine (also an Evil Weapon) in Warhammer Fantasy was wielded by the Elven God of War Khaine. To drive back the first incursion of Chaos, the first Elven king picked up the sword, and after defeating the Big Bad but not destroying it, it gradually turned him evil causing a sundering between the elf factions (one being led by his illegitimate son) and a civil war that continues to this day. The Dark Elves led by his son are still trying to reclaim the sword where it lies on its altar, which would give them to defeat the High Elves and possibly any further Chaos Incursions - it's possibly the most powerful weapon in Warhammer.
The Crown of Sorcery (more accurately called the Crown of Nagash) grants whoever puts it on tremendous magical powers, but also allows part of the spirit of Nagash the Supreme Necromancer to speak to them. It influenced the creation of at least one culture devoted to necromancy before it was locked away.
Oh yeah, and both of the above artifacts will eventually result in you being absorbed into their original owner.
And there's a story about the Head of Vecna, which is supposedly used in the same way, but doesn't actually do what the user expects. It does, however, do exactly what anyone with an ounce of sense expects.
Even if it did work as advertised, it would still be a tremendously stupid idea to use it. His hand turns you evil, imagine what his brain would do.
Another Artifact of Doom associated with Vecna is the Sword of Kas, a weapon he made and gave to his second-in-command, Kas the Bloody Handed. Kas turned against him, and the resulting battle between the armies of the two evil beings killed both of them, leaving only the Sword and Vecna's Hand and Eye behind. Both were Not Quite Dead, of course; Vecna, as stated, became a demigod, while Kas became a very powerful vampire. The Sword of Kas is said to be a potent weapon for anyone who would oppose Vecna, but it is incredibly evil, and a hero who tries to use it for this purpose risks turning into a bloody, merciless warlord like Kas himself.
The Demon Lord Orcus (the one who has a Trope named after him) owns one of the most dreaded artifacts in the game, the Wand of Orcus, which is actually a rod topped with a skull. (In the 4th Edition, the shaft is part of a vertebra.) Orcus rarely lets it out of his sight, but some sources say that he "lends" it to worshippers occasionally to spread evil and chaos. The Wand not only kills victims, it turns them into powerful undead monsters under Orcus' control. (Just which type depends on which edition of the game.) No-one can agree on just who the skull used to belong to; some claim it was a god of goodness and light who Orcus murdered, while others say it was a great mortal hero who challenged him and failed (though, if that is true, magic must have been used to enlarge it). Whatever the case, the goodness of the soul the skull once belonged to has been corrupted into blackest evil.
Evil-aligned artifacts in Dungeons & Dragons generally act like this; the Book of Vile DarknessSourcebook lists some, and is named after a particular example.
4e has taken this to its logical extreme with the Heart of the Abyss; a shard of pure evil. Asmodeus stole a sliver off the shard, crafted it into a rod, and used it to kill the strongest of the gods. The BloodWar fought between the devils and demons was spawned by this; Asmodeus wants the rest of the shard for himself, and the demons want the piece he stole back.
The Book of Vile Darkness is, itself, a cursed artifact of sorts in Dungeons & Dragons. Originally penned by a race that seeks to kill deities, other evil wizards, including Vecna, contributed to it, and it is now a spellbook that contains some of the most vile magic known.
The Book of Keeping is not truly a cursed artifact, but still a dangerous one in the Dungeons & Dragons world. This book contains information on summoning powerful yugoloths, even giving the true names of a few of them. No-one knows who wrote it - given that he would likely be the yugoloths' most hated enemy, he may no longer be alive. At least four copies of the Book exist, although some say as many as seven, and their owners tend to change frequently.
Notably, even some good artifacts are like this. It's not so much that they're overtly malicious, as opposed to either being unforgiving or intended for someone else. They don't necessarily mind being used for a bit, but be respectful.
It is pretty much the rule for all major Artifacts throughout D&D that each of them must come with some curse. If it ain't cursed, it ain't an Artifact. This was stated explicitly in the 2nd Edition AD&D Book of Artifacts, and is implied elsewhere.
Exalted gives us The Broken-Winged Crane, the ultimate Tome of Eldritch Lore in the setting. Just reading it requires the unfortunate bastard in question to make a high-difficulty Willpower roll; if they fail, they pick up a form of insanity involving obsession over the tome and its contents. Its many-storied lore paints its various copies as imperfect reflections of the true tome that will come into existence at the dawn of a new dark age of Creation. In reality, the "true" copy is the book the Scarlet Empress wrote to try to wrest immortality from the Yozis. Thatdid notgo well.
Every artifact in Houses Of The Blooded. It's written into the rules: they can give you great power, but once a season, the Narrator can cause you to automatically fail a roll by saying "DOOOOOOOM!" A good Narrator will do this at the worst possible time.
Kult has rules for possessed or otherwise evil items. One example is a machine gun that, when picked up, causes the wielder to go on a murdeous rampage, shooting everything in sight, friend or foe.
The Ring of the Nibelungs from Richard Wagner's operatic cycle of the same name, cursed by its maker to destroy all who possess or covet it. The curse comes with a truly ominous Leitmotif, which plays every time someone is killed because of it. Wagner, in loosely adapting the Norse Mythology example above, extended the symbolism of the lust for gold, relating it (in typical 19th c. fashion) to the "Wille zur Macht", the fundamental anti-social aspect of which he symbolized in the idea that the Ring could be made only by one who had renounced all natural affections.
There are a few in the attractions at Disney Theme Parks. A notable one is in the Indiana Jones sequence of The Great Movie Ride, where a real-life Cast Member plays the role of the poor fool who tries to take it.
The Ignika in BIONICLE. On top of that, it was made exactly like the One Ring.
The titular Halo Array is a network of ancient stellar megastructures scattered across the galaxy. When activated from Installation 00 - the Ark - in a single, synchronized event, the Halo Array annihilates all thinking life in the galaxy - including the local Eldritch Abomination.
The Forerunners who built the Array were forced to fire this weapon to end the Flood threat; they were believed to have all perished and fall into extinction as a result, but not before they ordered their AIs to reseed life across the galaxy postbellum with the specimens they had gathered and sheltered for preservation.
The entire Halo trilogy - the first three games - is spent trying to stop the Covenant from activating the Halos in their demented belief that doing so will make them into Gods... while also preventing the resurgent Flood from eating every living thing in sight at the same time.
The Apple, aka one of the Pieces of Eden from the Assassin's Creed series. As observed by Altaďr in the Codex, where he states "I freed myself. But now I wonder... Did I really? For here I sit ďż˝ desperate to understand that which I swore to destroy.".
Other Pieces are even worse. The Shroud tries to get people to use it to heal themselves or others with a Compelling Voice, but it is either actively malevolent or just very, very broken. The results range from Body Horror to Came Back Wrong. Occasionally, it will actually heal someone.
Subverted since the true purpose of the Pieces of Eden (at least seen in the games) is to avert global destruction in the near future.
Interestingly, in "The Tyranny of King Washington" DLC, it appears that this is the effect of the Apple that was given to George Washington, who then goes on to turn the new United States into a dictatorship bent on world domination. However, it was all a warning by the Apple as a vision. Seeing the vision horrified Washington into rejecting the idea of a monarchy out of hand and he chews out the next person who suggests it who is really a hallucination embodying his lingering ambitions.
The demonic sword Soul Edge from the Soul Series of fighting games. The sword invades the mind of its wielder and turns it into its host body, removing his self-consciousness and turning him into a bloodlusting machine whose only goal is to offer the souls of those he slay to the sword. The sword's influence can also affect the user's physical appearance in varying degrees, the most common effect being a demon-looking deformed arm.
In Soul Calibur IV, some of the characters' story paths imply that Soul Calibur, the "good" counterpart of Soul Edge, may be evil as well. In one ending, it "covers the world with crystals in an eternal utopia"; essentially trapping the world in stasis forever.
Confirmed in Soul Calibur V: Soul Calibur has an avatar named Elysium living within it (just as Soul Edge has Inferno) who seeks this "eternal utopia", and takes the form of Sophitia to trick Patroklos into doing its bidding.
In Ultima IV, one can acquire an item called the "Skull of Mondain" (the villain of the very first Ultima) that can instantly destroy your enemies. However, it also destroys your Karma Meter to the point that some people claim it makes the game Unwinnable (it doesn't, but each use brings you a quarter of the way from Incorruptible Pure Pureness to evil in every virtue). Particularly sneaky, since the notion of a Karma Meter was new at the time.
In the Human campaign, the runesword Frostmourne (a clear knockoff ofHomage to Elric's Stormbringer) curses Arthas.
In the Orc campaign, the blood of the Pit Lord Mannoroth corrupts Grom Hellscream and his band, turning them into Chaos Orcs.
In the night elf campaign, the Skull of Gul'Dan (a powerful warlock) turns Illidan Stormrage into a mighty demon, and after using his new powers to defeat the Dreadlord Tichondrius (a major threat to the night elves), he's exiled by his brother for being tainted with evil. In the expansion pack, he does end up becoming evil, so maybe his brother was on to something. (Although Illidan's problems go far beyond the artifact he absorbed, and it's not been directly confirmed that the Skull sent him over the edge.)
He also acquires the Eye of Sargeras (the actual eye of a corrupted titan who became pure evil, ironically created the Burning Legion which possessed the Skull of Gul'dan and which Tichondrious was a lieutenant in) in the expansion, which is to be one of those too, having the power to kill people on the other side of the world (shattering the world in the process).
The novels bring us the Demon Soul, probably the worst of them all. Created by one of the Dragon Aspects under the influence of eldritch abominations, it's immensely powerful (among other things, it can control all dragons except its creator and affects its user much like the One Ring does). Even the eldritch abominations end up underestimating that attraction, and their scheme fails as a result. It's almost certainly an homage to the One Ring, as it appears to be a plain, unmarked gold disc (as the ring is a "simple gold ring"). This one is also the reason there's now a flaming god-dragon kept together by metal plates flying around destroying the world in World of Warcraft. He didn't use to look like that.
The uncorrupted Dragon Soul returns via Time Travel, and is used to destroy its own creator in the final battle of Cataclysm.
Red Lyrium is set to make a comeback in Dragon Age: Inquisition, having fallen into the hands of the "Red Templars", who apparently are using it as a substitute for the regular Lyrium they are addicted too. The results aren't exactly pretty.
To a lesser degree, the Eluvian, although it was originally a perfectly "normal" Magic Mirror before the Darkspawn got to it. Merrill believes that repairing it (even if it takes dealing with demons) could restore some lost elven heritage, while her mentor doesn't think it's worth the risk. In the end, we never find out what it would have done. According to her mentor, the real problem wasn't the Eluvian itself but rather the Pride demon (the same one Merrill dealt with to repair the Eluvian) that was waiting on the other side.
Vigilance, the sword forged by Wade for the Warden-Commander from the bones of an Ancient Dragon. The epilogue of Awakening claims it was later stolen by the Antivan Crows and rumours abound that it's steadily growing in power and possesses a will of it's own.
The Frozen Flame, from Chrono Cross. It's one of the most desirable "treasure" of El Nido and almost everyone want to get it and have a life of fortune. In reality however it's a fragment of Lavos, and if you aren't the Arbiter (Serge, the 17 year old boy that lives on Arni Village), having contact with it results in death. Oh, and it's also the source of power of Chronopolis and it can't be accesed because the arbiter is now someone else. In a nutshell the thing is wanted by every single Big Bad of the game.
The The Legend of Zelda: Majora's Mask. To put it in perspective; everything wrong in Termina when you get there? All of it was done either directly or indirectly by the Skull Kid wearing the Mask. And on top of ruining everyone's lives, he's planning to drop the frickin'moon, destroying the entire land of Termina. And he can do it. Oh, and it's not just a power-up artifact of doom: the mask is intelligent, and is possessing the Skull Kid. And when Majora decides he's outlived his usefulness, the mask discards the kid like an old pair of socks.
The Legend of Zelda: Twilight Princess has the Fused Shadows, which are hyped up to be an Artifact of Doom by the Light Spirits that Link rescues throughout the game. However, they all agree that, despite the potential for evil the Shadows hold, Link needs to collect them in order to have a chance of challenging Zant's power. Their power is proven when Link fights the creatures that possess them, which have grown into horrific beasts of great power: a Deku Baba, one of the least dangerous monsters in the game, became an enormous two-headed creature that could swallow a man whole when it grabbed a Shadow. We never do see them exert a corrupting power over Link or Midna, though... presumably they were too pure-hearted to be affected (and Midna is eventually revealed to be the rightful possessor of their power anyway, so it makes sense it wouldn't affect her).
The Mirror of Twilight from the same game turns demure, unassuming Yeta into the crazy ice-monster Blizzeta.
"NOT TAKE MIRROR!"
Super Paper Mario has the Chaos Heart, which Big Bad Count Bleck creates by forcing the marriage of Bowser and Peach and uses to set in motion the end of the universe.
The prequel Paper Mario: The Thousand-Year Door was built around an Artifact of Doom: Simply opening the damn door could doom the entire universe, and had already blown Rogueport sky high once.
Final Fantasy VII had the Black Materia whose only purpose (that was explained to the player at least) would bring a cataclysmic force against the planet and destroy it. On fear that Sephiroth would get through all of the traps and bosses and gain it for himself, the party of heroes decide to head in and retrieve it for themselves to keep it safe. At that point, the indoctrination kicks in and Cloud delivers the goods.
A interesting example is the True Rune of Punishment from Suikoden IV By the time characters figure out what it is, the rune has killed EVERYONE who is seen using it. In an optional scene, the main character can overhear a discussion where other characters discuss who is going to get the rune next after it kills the main character!
Subverted after gathering the 108 Stars which requires forgiving Snowe, whose cowardice and mistakes in the beginning of the game led to the main character's exile and disgrace in the first place. The Rune of Punishment governs atonement and forgiveness, so this act shifts it into the "forgiveness" phase. The final attack granted by the Rune of Punishment actually heals the main character instead of taking away his health like the earlier attacks (which also lose their Cast From HP effects after the Rune shifts to forgiveness). He even avoids dying in the end.
This is why most of the 27 True Runes are bad ideas for anyone to use. The Sun Rune of Suikoden V grants nearly God-like power, but at the cost of their sanity. The Soul Eater Rune from the original Suikodenwill eventually kill the user's dearest friends and family to become more powerful. The Bright Shield and Black Sword runes are fine in and of themselves, but only two people that are close to one another (friends, family, etc) can use them, and they will be forced by the runes to fight each other. The True Elemental Runes (Fire, Water, Lightning, Wind and Earth) are trying to gain dominance over each other by forcing their hosts to over-use their powers.
Actually loss of sanity is not common at all among True Runes; the only reason the Sun Rune has this effect is because it is in fact broken and requires two control runes branded on each hands to use properly. One of these runes was stolen prior to the events of the game and thus it's bearer could not withstand it's mind altering effects.
The Terror Mask from the Splatterhouse series is a sentient, diabolic mask (roughly shaped like a grinning skull) that grants its wearer tremendous power. Its true goal is a Batman Gambit to take over Hell.
In the Chzo Mythos series of games, there are quite a few Artifacts of Doom, the most obvious being the cursed idol that innocently sits in a bell jar in the first game until the jar gets broken.
In the game based on the manga of the same name, the Anubis Stand from JoJo's Bizarre Adventure is the Stand of a sword, rather then a living being. In a similar way to the above Soul Edge, the Anubis Stand possesses whoever removes it from its scabbard and turns them homicidally insane. Three characters in the game (all from the manga) use the sword while being controlled by the Anubis Stand. The Anubis Stand is still capable of controlling others even when the sword had been broken into pieces by Jotaro (although its attempts to make a child throw a large piece of the sword at Jotaro's back leads to the stand's defeat as it ends up at the bottom of the River Nile).
Phazon from the Metroid Prime series. The Space Pirates (and, in the third game, The Federation) seem to think it's just a nifty Applied Phlebotinum that gives them lots of power. It is, however, strongly implied that Phazon has its own sentience and desires to spread and corrupt everything.
The Federation knows about the corrupting effects of Phazon. That's why they hire Samus to help them get rid of it all. They just like the extra power it gives in the short term.
The Elder Scrolls series is positively rife with them. Each game seems to feature at least one as part of its main quest, with others showing up in the side quests or deep backstory.
Arena features the Staff of Chaos. The Imperial Battlemage Jagar Tharn used it to imprison the emperor and usurp his throne. He then broke it into pieces which the Eternal Champion has to recover.
Morrowind has the Heart of Lorkhan. The literal heart of the dead creator god. The Dwemer tapped into it using the "tools of Kagrenac" (Wraithguard, Keening, and Sunder) causing them to disappear. Dagoth Ur and the Tribunal then used the tools and the heart to achieve divinity. The Nerevarine will need to gather the tools and destroy the heart in order to defeat Dagoth Ur.
Arguably also the ash statues, that connect people to Dagoth Ur and slowly infect them with corprus.
Another example would be the sword Umbra. The sword absorbs the souls of the people it kills and corrupts the wielder.
Curiously, using the sword has NO downside whatsoever in game; it's just a really powerful sword with great soul capturing ability. The fact that the sword reappears in different games with different owners is a tad ominous...
Even weirder, you can enchant your own weapons to have the same effect as Umbra with no side effects to you or the weapon, despite Umbra supposedly being some incredibly rare uber-evil artifact.
To be fair the corruption is implied to be somewhat slow, especially on the mighty warrior your character is supposed to be by the time they can actually win the damn fight. Morrowind's Umbra claims to have wielded it for a long time, and seen several wars with it, and the next Umbra was a somewhat unskilled warrior so could have fallen to its corruption much quicker (With Great Power Comes Great Insanity and all that).
In The Elder Scrolls novels, Umbra is too much for even Clavicus Vile, a Daedric Prince, to handle. It steals a good chunk of his power before he manages to get rid of it.
Speaking of corruption: There are a few more (mostly daedric) artifacts that could probably qualify for this rope. Such as the aptly named Skull of Corruption, which in Skyrim steals dreams of people and gives them nightmares or Mehrunes Razor, though, admittedly, for most of the daedric artifacts it's actually only an 'air' of doom that is often also created by the way they are acquired, such as the Ring of Namira in Skyrim, for which you have to lure a priest to a cave and eat him together with a coven of cannibals.
The Mani Mani from Earthbound is very desirable, and emits an aura that causes anyone who gets near it to be consumed with greed. These factors allow it to play a prominent role in getting the Big Bad to rise to power.
The web-based MMORPG Mojo Ave had the ultimate example of an Artifact of Doom: "The Skull of Tony Teulan", a usable item which has the effect of turning off the game. Not the game of the user who used it, the entire game for everyone. Since there was no way to reverse the effect, it only got used once.
The Keyblades from Kingdom Hearts shattered the world from one large one into millions of small isolated world-shards, due to a war between good Keyblade wielders and evil ones (the shards were saved from total destruction by the hearts of children, although the good keyblade wielders may have helped). Not for nothing is the general reaction of people who recognize the Keyblades for what they are something along the lines of "oh god, get away from my world-shard NOW".
The Marker from Dead Space. Subverted. It's actually a government-manufactured copy of the real one.
Doubly subverted in that it's not that the Marker itself is the Artifact of Doom. The Marker is, in fact, a sentient containment device for the Big Bad that spawns the Necromorphs. It's also what creates the titular "dead space"- an energy field that repels the Necromorphs.
Even if it does create the dead space that suppresses the Necromorphs, the Marker still makes people slowly go crazy, see their dead relatives, write strange messages on the wall in their own blood, and kill themselves.
In Dead Space 2, Isaac inadvertently creates another Marker that does all the same things minus the supression, that almost starts something called a convergence event.
Dead Space 3 reveals the Markers' true purpose, and it is ghastly. They are the tools an incomplete post-convergence Necromorph is using to gather the raw material it needs to make itself whole.
The Artifacts from Unreal II: The Awakening. Your boss sends you off to gather the bits under the guise of beating the corporations/etc. to the punch, but he's really gone mad with power. When he finally gets all the bits together and assembles it, it turns the previously innocent alien chef/janitor/etc. folk into giant monstrous things with hands that shoot singularities that will kill anything in a single hit. Even themselves. After killing one, you get to use one of their hands as a weapon... and with who knows how many of them crawling over the ship. Let's just say you'll need it.
The Celestial Stone in Bomberman 64: The Second Attack is a priceless gem that's said to contain limitless power, but much of it's story is forgotten by time, so it's only natural that when a space pirate finally locates the stone, his body is possessed by an ancient demon god of chaos.
The Star Forge in Knights of the Old Republic. Described as "an artifact of The Dark Side", it's a piece of Magitek that feeds off the evil impulses of those who use it. According to the sequel, only a strong-willed individual can use it with anything approaching safety.
At least Revan was a bit Genre Savvy about it, unlike Malak...
In one installment of Curiosities of Lotus Asia (a series of side stories to Touhou written by the creator), Rinnosuke Morichika gets "artifact of doom" vibes, via his ability to see the name and purpose of an object (but nothowit is used), from a Game Boy. He spends most of the story agonizing whether he should allow it to fall into the hands of local Reality Warper Yukari Yakumo. (To be fair, it does allow you to "control a world", so to speak...)
Rinnosuke does eventually decide to destroy it and attempts to smash it with a mallet, only to have Yukari stick her hand through one of her gaps and catch the mallet, waggle a finger at Rinnosuke, and take said artifact, leaving Rinnosuke dumbstruck.
The Demon Crown in Cave Story. The ultimate irony is that Misery, who is enthralled by the Crown's curse, was the one who had it made in the first place, most likely in a bid for power.
Fallout 3 gives us the ominous, Lovecraftian obelisk in the Dunwich Building's Virulent Underchambers. Not the cause of any doom so far, but it did drive Jaime pretty insane, and you do hear those "dark whispers of power" mentioned in the article description when around it. Point Lookout added the Krivbeknih (Necronomicon knock-off) into the mix, which you can destroy by pressing it against the obelisk, which absorbs the book and grows in power.
In Vanguard Bandits, the excavated ATAC Zulwarn has the power to possess its rider's enemies; according to the worst ending, it can also grant immortality. Unfortunately, it also has a tendency to overwhelm its rider's mind and make them into megalomaniacs. This happens to Puck in the Ruin Path ending. It's not clear whether Faulkner was possessed or was evil enough for Zulwarn's approval. Zulwarn is so evil that merely activating it requires mass human sacrifice since it's powered by blood. Though Puck finds a way to reduce the requirement down to a few drops.
Mortal Kombat Deception introduced the Datusha Kris, Ashrah's weapon of choice. Originally said to purify its user with each evil slain, MK:Armageddon revealed it was a sentient-sword that manipulates (or even forces) its user into becoming a Blood Knight, apparently so it can use itself on slaughtering the Vampire race, of which the kris is its only "natural" enemy.
Pandora's Box fits this Trope in most settings, but in God of War, it was probably more responsible than Kratos was for what happened. The whole plot starts when Ares opens it, and the evils within it proceed to corrupt the other gods with the evils of the Titanomachy, which caused them to become paranoid and power hungry. Zeus himself fell prey to Fear, causing him to begin his campaign to destroy Kratos and ultimately betray him. In the third game, as Kratos slays each infected god, the evils of the Box are released upon the world, causing cataclysms. When Kratos finally gets ahold of it, he finds it empty, and... then the trouble really starts.
The Artifact from Doom 3. It was created by the forces of Hell to counter the Soul Cube the martians created to fight them, and to act as a key many years later, when humanity has colonized Mars. It gives the wielder the powers of super speed, One-Hit Kill, super strength and invulnerability but it has to be fueled by human souls and as long as it's on the living world, Hell'll always have a way into the world and the only way to make sure that Hell wouldn't conquer Earth is to destroy The Artifact in Hell for good... which Betruger will not tolerate.
The Shabby Doll from Silent Hill 4, which causes unremovable hauntings if you put it in the item chest.
The Patriots in the Metal Gear Solid series are in fact four computers built by the aging leader of a conspiracy who no longer trusted his co-conspirators to be completely loyal to the cause. Eventually they did no longer obey him, kept him as their prisoner, and went for full out world domination.
Nethack has some dangerous items, such as the Cursed Potion of Sickness and the Amulet of Strangulation.
Ancient Domains of Mystery has a Ring of Doom, which, once worn, can only be removed by uncursing the ring in some manner (at which point it retains the dooming effects, but may be removed... but will curse itself again if worn again). Many other items in the game are also "autocursing", including some literal artifacts. Particularly nasty artifacts include the Scythe of Corruption and the Medal of Chaos, both of which, in addition to autocursing, corrupt the player.
The ARI from Heavy Rain, since it's highly addictive, and can eventually kill Norman Jayden, the character using it. If it does, his Cowboy Cop partner Blake puts it on, and he sees a digital version of Jayden standing over him, with a scary smirk on his face.
In Mass Effect 2, there's a Reaper which died 37 million years ago. It still indoctrinates people.
"Even dead gods can dream."
In the mission Arrival, a science team discovers Object Rho, a Reaper artifact which indoctrinated the scientists to make them lure Shepard into a trap.
Any Reaper tech can act like this. Even the seemingly simply Dragon's Teeth can brainwash nearby people into impaling themselves on the spikes, thus transforming into Husks.
The Nox Nyctores from the BlazBlue series have fairly nasty side effects. Tsubaki's Izayoi which eventually robs its user of sight is so nasty that Ragna's arcade win quote consists of him recognizing it and warning Tsubaki that she should get rid of it as soon as possible.
It is arguable that Ragna isn't one to talk, though. Especially not considering the fact that his Red Right Hand is the Blaz Blue, an artifact of doom that, if he ever lost control over it, could spawn a monster with the potential to destroy what is left of the world.
Street Fighter X Tekken has Pandora, a box-shaped artifact from space that reacts to conflict from around the world, greatly augmenting the fighting abilities and physical prowess of those that are affected by it, but at the cost of potentially corrupting their souls.
The Skull Heart from Skullgirls. Supposedly, a woman (it doesn't work for males) who makes a wish on the Heart will have it granted, but only if her intentions are pure enough. If there's even the least taint of corruption within her, the Heart will mutate her into a demonic, supernaturally powerful being, one of the Skullgirls. Fourteen years prior to the events of the game, Squigly's mother was in possession of one from Double, when Dahila and her goons busted in and killed everyone in the party including Squigly herself, she wished for her family to return, but in sense of desperation at the loss of her family, she became the Skullgirl, and her family her servants. Seven years later, the game world is recovering from the aftermath of a long war that screeched to a halt when a powerful queen got hold of the Skull Heart and wished for peace; she got her wish, but in a rather twisted fashion — she was turned into the most dangerous Skullgirl of all time, and the quarreling nations had to stop the war in order to concentrate on the task of killing her before she could destroy them all. Even worse, one of the characters' endings reveals that the Skull Heart is sentient, and actually ''wants'' to create more Skullgirls.
The Chaos Emeralds from the Sonic the Hedgehog series become this in the wrong hands; they've been revealed to be the power source for a BFG enormous cannon held within a space station, and said cannon can end the world when at full power.
Spoofed in the second Fantasy Quest game with the Golden Cufflink of Fire. You never learn precisely what it does, and the villain who possesses it is a bit of a joke.
Department 42: The Mystery of the Nine involves the recovery of nine cursed artifacts with a limited intelligence that enabled them to escape the safekeeping of the titular agency and do various funky things to their unlucky possessors.
Shin Megami Tensei III: Nocturne has several. First and foremost, the Magatama - demonic parasites/symbiotes used as combination of armor and spellbook, capable of transforming humans into half-demons. This ability alone is enough to make them inscrutably dangerous, and considering the apparent maker, this can't be a good thing. There are also several cursed items called Deathstones, slivers of misfortune and death, used in devil fusion to summon the Incarnations of Death as servants, and can only be found as you progress in the Labyrinth of Amala. Finally, the Amala technology strewn around the Vortex World serves as the game's Akashic Records, but peering too deeply into the knowledge the drums offer is a surefire way to irreversible insanity.
The Messiah Armor in Duel Savior Destiny has been cursed by the failure of Messiah candidates who put it on before and the grudges that infested it. While it can turn someone into the Messiah, they'll go on a killing rampage and risk destroying the world which is exactly what the Messiah is actually supposed to do, leaving it questionable what the curse on it truly does.
The Relic of Moirai in Contra: Shattered Soldier is revealed to be the mysterious force that the alien attackers were trying to recover, but it was taken and hidden by the Triumvirate, as revealed by Lance Bean after you defeat him.
In Gyossait, the eldritch organs of the titular Earth goddess can mutate mortals into horrifying gods.
Runescape has several quests that involve artifacts of doom. The Stone of Jas is a artifact containing a nearly limitless amount of power, it is the original source of the runestones that are needed for casting spells in the game and touching it briefly during a quest causes your combat levels to temporarily increase to more than double the maximum level you can reach by training. Prolonged contact with it can turn a mortal into a god. However, it has a huge price for using. When somebody uses the stone of Jas, the Dragonkin, a race that is cursed with protecting the stone, become enraged to the point of turning into Omnicidal Maniac until they calm down by committing acts of destruction. And every time somebody uses the stone their power increases, currently they have nearly become gods themselves.
Though on the plus side it has no direct effect on the users sanity unlike many of the powerful Artifacts on this page, and there is at least one Dragonkin who has not yet gone insane and they wish to free themselves of the curse, so if someone managed to break the curse by working with the sane Dragonkin, they could use the stone without needing to worry about the Dragonkin as the Dragonkin would now most likely try to get revenge on Jas.
The black block from Antichamber. It floats around emitting darkness wherever it goes, and tends to show up right as you get to gun upgrade rooms. What it is, what it is doing, and why it tends to pass by the block guns is never touched upon at all. However, it's a prominent moving thing doing something, so it's worth investigating.
The Master Crown in Kirby's Return to Dream Land gives off this vibe. On a closer observation, it appears to be controlling Magolor, as it has a tendency to squirm around shortly before he performs many of his attacks and it takes on an appearance reminiscent of a parasite while he's using it. Magolor Soul is also described as being an Empty Shell that's been possessed by its power, which further implies that the thing has a will of its own.
The Book of E-Ville from Sluggy Freelance. Or at least that's how most of the characters treat it. While it contains more than one spell for summoning world-destroying demons, it has yet to actually do much of anything malevolent aside from following Gwynn around.
In Goblins, the Axe of Piridan is a major subversion: while Big-Ears initially senses a palpaple aura of evil around it, and we initially see it in the hands of a monster, it's actually a Good weapon. The aura comes from the fact that it's a Restraining Bolt against a powerful demon, and it won't hurt a Paladin unless the Paladin wants it too... which is unlikely at best.
The Shield of Wonder is a straight example: it provides a random, usually very squicky, effect each time it blocks a weapon.
In The Order of the Stick, the Crimson Mantle arguably qualifies. It's not clear that it has any direct control over the wearer, but it does give a divine command to enact a plan that could destroy all reality. It also halts the bearer's aging, which has the apparent side effect of preventing the bearer from maturing as well. Its current bearer is, in many ways, still the angry vengeful teenager he was when he first took up the Mantle.
Caliborn believes that the puppet Lil' Cal is a juju, an artifact whose sole purpose is to turn the lives of everyone who lives in the same universe with it into a nightmare. Turns out he is the reason Lil' Cal is so dangerous, because Lil' Cal is destined to be his Soul Jar.
In Endstone, the Banestone. The most powerful overstone, and it drives its rockers mad.
In Consequences of Choice The Invisus is a powerful stone entrusted to the class of Necromancers by the demigods of death.
Windows installation disks are treated this way in User Friendly. One was once microwaved (with the goal of creating the pretty effect created inthe plastic by destroying a CD this way). It crashed the microwave. Piotr suggested putting an Elder Sign Seal on it and leaving it alone.
Collecting and containing these is the whole point of the fictional SCP Foundation. The SCP Foundation has dozens of these, given the classification "keter" from the Hebrew word "crown", which is used in Qabalah to describe the highest principle of the universe. The methods used to contain these things are... intricate. The "euclid" and "safe" ones are easier to contain but most of them are still incredibly dangerous.
Some of the artifacts aren't in any way evil or malevolent, but could end up destroying the world anyway, often very weirdly. Like by burying the whole world under cakes, or causing everyone in the world to ignore basic biological necessities in favour of arguing over some trivial subject.
Some of the creepiest artifacts are ones that are not, in themselves, in any way dangerous but allow access to things that are so obviously too dangerous to experiment with that they should be left sealed away but, given the SCP Foundation's nature, aren't being left alone. There are literally whole universes filled with things they should obviously leave alone but aren't.
There's even a set of loosely-interconnected drabbles about the many ways Safe-category SCPs could end humanity and/or the world. Like the peace-inducing doves.
Tech Infantry has the magical sword Kuar, which grants you invisibility and increasing magical power, then sucks out our soul. There is also The Orb, a mystical artifact of untold power which is sought by the Caal.
The Book of Stories in the eponymous The Book of Stories OCT is as old as time and holds every Story ever told in every World. It's on its way of becoming this due to a mistake one of its guardians made.
The Heart of Darkness in The Gungan Council corrupts Phylis Alince into rallying The Alliance in attacking the Sith en masse and nearly converts her to the dark side.
Linkara'sMagic Gun is a subversion of this. The cultists who created intended it to be a a weapon powered by pure hate and agony, and used their own daughter to power it. But the weapon backfired, killed them, and the spirit inside the gun eventually became more benevolent and a partner of sorts to Linkara.
In the 90s' Spider-Mananimated series, the Evil Feels Good factor of the alien costume was added, with him growing more dependent upon the suit the longer he used it.
In the animated series based on Wildcats, the series MacGuffin that the heroes and villains are in a desperate race to find, the Orb, is an artifact left behind by the Precursors on Earth that can give anyone power on a cosmic scale. It's also evil to the core, possibly more evil than the Big Bad himself. Guess the Precursors hid the thing on Earth for good reason.
The Eye of Odin from Gargoyles isn't exactly evil, but it is incredibly dangerous to use because it enhances the dominant trait of the users' personality into what often amounts to a Superpowered Evil Side. Fox became a werewolf, and Goliath became a godlike Knight Templar. The only people who seem to be able to use the Eye safely are Odin himself and the Archmage, who was already a crazy Evil Sorcerer.
This stands in contrast to the Phoenix Gate, which is a subversion. Though many groups in the setting desire it as readily-accessible time travel, it only allows the creation of a Stable Time Loop. Fans have inferred this to mean something else is controlling the gate and its users.
A few Shen Gong Wu from Xiaolin Showdown probably qualified. One that definitely qualified was the Sapphire Dragon.
Spoofed to epic levels on The Venture Bros.. The ORB in is a small round device constructed by the greatest minds in history over hundreds of years, with the power to destroy the world. It is so feared that the Guild of Calamitous Intent, the OSI and the Venture Family each set up decades-spanning Batman Gambits to keep it from falling into the wrong hands. After all that fuss, it turns out that over 100 years ago, someone had the good sense to just break the stupid thing to keep it from causing trouble. Thus the century-long conflict over the ORB was a complete waste of time.
The Aladdin: The Series episode "Armored and Dangerous" has the invincible armor of Kileem, a powerful warlord who was undefeated in battle generations ago. The Sultan, who puts on the armor in order to stop a minotaur threatening Agrabah, becomes invulnerable and immensely strong, but is possessed by the spirit of Kileem, who turns out to be an inflammable tyrant and warmonger, who not only plans to conquer the Seven Deserts and later the world but condemns Jasmine to death for resisting him. Aladdin stops him by tricking him into destroying the statue that is the source of Kileem's power, releasing the Sultan from his control and saving Jasmine.
From Wakfu, the Eliacube is the most powerful artifact in the world, created as the acme of the magical science of the Eliatrope race. It acts as a very efficient Amplifier Artifact as long as it is feed with wakfu — the magic lifeforce found in all plants and beings. At first, you could think its great potential was simply misused by Nox, who's a madman, but the Start of Darkness episode "Noximilien" reveals that, 200 years before, the Eliacube already exercised a dangerous fascination over Nox, slowly turning him obsessed and insane.
To further prove the point, it also drove his dog insane.
The second episode of Danny Phantom circles around an amulet with a bright green gem that causes the bearer to transform into the spirit of the Dragon of Aaragon when angry.
The two-part episode of Adventure Time where Finn and Jake went through Ice King's tapes revealed his crown to be one. It gives the wearer immense magical power and immortality... while simultaneously slowly driving them to utter madness and amnesia, aware of their mental degeneration the entire time.
Notably, an Alternate Universe saw Finn suffering the same possession, minus the slowly part.
This has led fans to come to the conclusion that Ice King/Simon must have had an amazing amount of self-control to last as long as he did. Even the final result of said Artifact of Doom's powers isn't nearly as bad as what could have happened in anyone else's hands.
In the animated Young Justice, the Helmet of Fate is this because of the much less equitable relationship between the spirit of the Lord of Order, Nabu, within and the wearer as compared to other versions. When someone puts on the Helmet of Fate, Nabu, the spirit in the helmet, takes over their body and becomes Doctor Fate. The wearer's mind become nothing more than a voice in Doctor Fate's head. The helmet can only be removed if Nabu wants it to. Since Nabu needs a body to keep order, the chances of him releasing the wearer from the helmet is slim. That wasn't so for Kid Flash and Aqualad when they donned the helmet in the episodes "Denial" and "Revelation" respectively. However, in the episode "Misplaced", John Zatara had to take his daughter Zatanna's place to free her, and has been his new body ever since. Nabu was kind enough, though, to relay Zatara's concerns about Zatanna joining the team.
A substance rather than an object, but otherwise, Dark Energon from Transformers Prime, which is said to be the blood of Unicron, fits the bill perfectly. Turns dead Cybertronians into mindless berserker zombies. Powers up Megatron, but likely at a horrible cost to his sanity... He claims he can hear Unicron speaking to him, and he probably wasn't hallucinating, but it'd probably be more reassuring if he was. Can also be hazardous to your health just to be in contact with... Just ask Arcee or Raf, the first became dizzy and sick after contact with the stuff, while Megatron nearly killed the latter with it.
If that wasn't bad enough, Megatron forged himself a sword made out of the stuff that shattered the Star Saber.
One final side effect was revealed during Predacons Rising. Anyone who dies with Dark Energon in their system is not allowed to enter the afterlife and can be possessed by Unicron as puppet.
The Inspiration Manifestation spell was inscribed on a stone tablet-like book covered in spikes and kept in a dark cave and guarded with a barred and locked gate. The spell itself also slowly corrupts the user.
It's been speculated that Gideon Gleeful's amulet from Gravity Falls is one, but nothing has been confirmed. The second book itself, though, is most likely the cause of Gideon's madness.
"Dodj or Daar" from The Amazing World of Gumball counts as one, as whatever punishment card you pull is made reality until the game finishes. This includes one player's arm doing whatever another's does, making you unable to walk on the ground due to it being 'lava', and most terrifying of all, making all the players physically unable to breathe. There's a reason Gumball and Darwin first hid the game under their bed, then threw it away.
Real gold rings in real life. Gold can't do anything by itself, its power is given by our superstition.
Many people believe that nuclear weapons are the real life version of this trope, since knowledge of nuclear weapons and the logic of Mutually Assured Destruction is self-perpetuating. In a classic Catch-22, it would take a civilization-ending event to put the nuclear genie back in the bottle (or in the best case, terminal global economic decline) and then it would become Sealed Evil in a Can.
Two Manhattan Project physicists, Henry K. Daghlian Jr. and Louis Slotin, died from radiation poisoning in two separate criticality accidents in 1945 and 1946 involving the same plutonium bomb core assembly. Said device became known as the "Demon Core".
After the second incident, the task force responsible for it quickly disposed of it by installing it in a Mark III nuclear bomb and shipping it to the Marshall Islands, where it was consumed in the Crossroads Able nuclear test. It didn't go down quietly: it detonated 710 yards from the aiming point, spoiling much of the test, and no-one could determine why. Whether it had been scheduled for that test, or the scientists just wanted to get rid of it fast, is unknown.
Some fundamentalist Christians seem to feel this way about practically any form of entertainment that is not perceived to be Biblical (rock music and Dungeons & Dragons are particularly popular targets). The Moral Substitute may or may not be allowed.
It is rumored that Shakespeare's Taming Of The Shrew is implied to be one. The rumor states that there is a malevolent spirit which tempts the reader to say bad things about women.