Amulet of Dependency

Sometimes a character finds, or manages to manufacture, an Amulet of Concentrated Awesome. This can be a risky endeavor. Sometimes the character goes on to become a successful superhero or supervillain, but sometimes that amulet turns out to be a Magic Feather, an Artifact of Death or an Artifact of Doom. And sometimes the Amulet of Concentrated Awesome turns out to be Blessed with Suck.

Using an Amulet of Dependency gives you great power or other benefits that you quickly come to rely on, so after a short time it's not exactly easy to live without it. It also exposes the user (and sometimes his allies as well) to an Achilles' Heel that could be exploited by an enemy, and a Mana Drain that weakens him without help from an enemy.

Though the trope name says "amulet", this trope isn't necessarily something that's been created deliberately, or something that deliberately came into the user's possession. It can be someting acquired accidently, a natural object, etc. It can also be a direct consequence or side effect of being Cursed with Awesome or Blessed with Suck, or part of a being's nature it was born with, such as supernatural beings that have certain vulnerabilities.

If the owner of the Amulet of Dependency is also carrying the Villain Ball, his response is usually to set up all sorts of Death Traps that the hero must survive to activate the Achilles Heel, thus setting the scene for Hero's Journey. If the hero is the owner of the Amulet of Dependency, he typically has the option of finding a way to get rid of it, but he usually succeeds only with great sacrifice and often must simultaneously prevent it from falling into the hands of the Big Bad. If a sympathetic Anti-Villain, The Woobie, etc., ends up with it, it's a crapshoot whether there's any hope of getting rid of it.

Can be An Aesop about illegal drugs, but it often isn't.

The Amulet of Dependency can also be:
 * An Achilles' Heel
 * An Artifact of Attraction
 * An Artifact of Death
 * An Artifact of Doom
 * An Immortality Inducer, such as a Soul Jar
 * An Unholy Holy Sword

Please put examples that are really just one of these in those tropes, and use the space below for examples that don't fit one of those.

Anime and Manga

 * The girls from Gunslinger Girl are given medication that follows their implants conditioning. As we're shown, the implants and conditioning already gives them extraordinary strength and skill at the cost of their previous memories and possibly their humanity. The medication that's supposed to help them along is also a crutch, with weird things happening to them should they be unable to take them, Triela becomes weak and unable to fight properly, while Angelica becomes so desperate to get her hands on a weapon she breaks Priscilla's wrist.

Comic Books

 * Dream/Morpheus in The Sandman and his ruby (or Materioptikon, as Doctor Destiny calls it), which he used as a tool to help him control his power, but placed so much in it that he was weakened and its loss helped guarantee his imprisonment. Decades later, its destruction by its wielder, Doctor Destiny, restored Dream to his full power when it was supposed to finish him.
 * But at the end of the series
 * The titular amulet in Amulet. It can be used to
 * The Marvel Cinematic Universe gave Iron Man one of these in the form of a removable and compact Arc Reactor, which he uses in this continuity to power both his heart magnet and his armor. The comic versions of the character previously used more integrated power sources like sunlight, kinetic energy and mains current though Tony's Bleeding Edge era designs have adopted the Reactor as well.

Fan Works

 * George's ring in With Strings Attached. It turns out to have bonded with him and contains part of his soul, though he doesn't find this out until it's forcibly removed from him. As he put it, it was like having his soul's arm ripped off.

Film

 * In Star Wars, many fans believe the decision to build the Death Star actually made The Empire easier to defeat.
 * Arguably, the Force itself can work like this. The more one taps into it and uses it, the more it uses them back, to the point of reducing everyone to a Cosmic Plaything and the Jedi / Sith even more so. At least that was Darth Traya's thinking.
 * The Dark Side of the Force tends to become this far more often as the mindset of the Sith makes them more desperate to maintain their physical bodies and by extension their power in the material universe, to the point where many older Dark Lords were fine with becoming husks sustained only by the Dark Side.
 * Lampshaded in The Matrix: The rebel humans are dependent on (presumably nonsentient) machines that power their life support and equipment; if their enemies were to find the rebel humans' vehicles and bases, or gain control of them, they could defeat the rebellion quickly. The humans could just turn off the machines, but they would probably die if they did.
 * The Expanded Universe makes it clear that the rebels are actually a part of the machines' system, serving as a sort of dumping ground for malcontents that might otherwise disturb the network.
 * In The Gods Must Be Crazy, a relatively primitive civilization discovers a modern Coca-Cola bottle. The tribesmen discover all sorts of positive uses for it, but the fact that they don't understand it and have only one leads to disputes, infighting, and injury. As a result, the hero goes on a quest to 'return it to the gods'.
 * Laserblast: A teenage boy finds an alien laser gun and necklace. He must wear the necklace to activate the laser gun, but doing so corrupts him into a monster.

Folklore

 * In Irish folklore Merrow are forced to wear a red-feathered hat called a cohuleen druith or else lose their water-breathing and shapeshifting powers. Similarly, Selkies are able to transform between human and seal using magical sealskins.
 * The logical extension of this is the tale that a handsome man comes across the hat, shawl, or animal pelt of a beautiful faerie maiden. He hides it and then forces the maiden to marry him. Years later, after bearing children for him, she comes across the article of clothing and then runs away to freedom.
 * A variation of the story is that the maiden never finds the sealskin and grows into an old woman, and it is her granddaughter who finds it. As the grandmother would die of old age if she put on the skin (as seals don't live as long as humans), she lets her granddaughter keep the skin and become a selkie herself.
 * There is a ghost story that goes like so: a young man encounters (or worse, marries) a beautiful woman, who later turns out to be a monster who removes its skin or detaches its head. The young man pours salt, embers, broken glass or some such on the skin or the sleeping body and when the monster returns it dies, either from poisoning/burning brought on by contact with the irritant or due to the resulting organ failure because it cannot reattach.
 * In traditional stories, werewolves were witches who commonly transformed by wearing a wolf-skin pelt or belt, and without the skin they were powerless. As in the ghost story, destroying the skin could have serious consequences.

Literature

 * In The Lord of the Rings, The One Ring is both an Artifact of Doom and a Soul Jar, but it deserves special mention here because it confers such powers on the user it is very tempting to use it to try to defeat Big Bad Sauron. Many of those tempted to use it don't understand that the Ring itself can never be used to defeat Sauron, as the Ring and the Dark Lord are one and the same. Plus, anybody with enough power to wield the Ring to even a fraction of its full potential will inevitably be corrupted by it. Sauron would still use other people's lust for the ring (like Saruman's) to his own advantage. And he did play a deep game with the other rings of power—giving great power to the elves and dwarves, but thereby making them vulnerable to his control through the Ruling Ring.
 * All the Rings are fundamentally Amulets of Dependency in their concept.
 * The Nine Rings given to Men granted the bearers power but soon they corrupted and enslaved their bearers, thus creating the Ring-Wraiths.
 * The Seven Rings given to Dwarves increased their ability to obtain gold, but also inflamed their love of gold and their pride to self-destructive levels.
 * The Three Elven Rings were expressly used to maintain the timelessness of the Elven Kingdoms of Lorien, Rivendell, and the Grey Havens. The core of their use was to allow the Elves to maintain the "Old" World while Middle-Earth steadily changed. This made them more and more disconnected from Middle Earth as it changed over time.
 * The One Ring increased Sauron's power over Middle Earth, but he put so much of his own essence into it that he was weaker without it and destroying it would destroy him. Some comments by Gandalf suggest that the One Ring actually made Sauron more evil (specifically, more bent on dominating others) than he had been previously.
 * The final product of the film and novel Perfume turns out to be this for the main character.
 * Voldemort's horcruxes in the Harry Potter series are an odd example: obsessed with the idea of immortality, he intentionally tore his soul to pieces through multiple acts of murder so he could hide them safely away inside specially-chosen objects. Ultimately, doing so has given him a critical weakness: if he ever feels so much as a shred of genuine remorse for his actions, his shattered soul will recombine, an experience so painful that it could well kill him. (This turns out to be the merciful option, as dying otherwise will condemn him to a Fate Worse Than Death.)
 * Zelazny's Chronicles of Amber brings this trope up a number of times, especially in the second half as it can then be tied into the concept of using raw power to cover for sloppiness and lack of forethought as habit-forming. Here using these stays as a viable if deprecated option.
 * In Jonathan Strange & Mr Norrell Norrell recounts how magicians would often seal some of their power in an object to prevent them being lost with illness or old age. Norrell explains that he resisted the temptation because the objects invariably get lost or stolen, weakening the magician even to the point of death unless they're retrieved.
 * The vampires of 19th century fiction are commonly tied to something of significance to them. Dracula was forced to sleep in contact with his native soil, Carmilla had to sleep in a coffin filled with the blood of her victims, and the brothers Ténèbre revived from repeated deaths by regenerating from within their tombs.

Live Action TV

 * The few times the Doctor has gone without his sonic screwdriver since 2005, the results have been mostly disastrous. Of course, he manages to get out of everything anyway, but still...
 * A lucky rabbit's foot appeared in Supernatural that turned one's luck really sour if it was ever lost.
 * Forever Knight had a case of this when Nick was 'cured' with Lidobuterine, a drug normally used in cattle. It made him bascially human, able to eat and be in the sun, but he got more and more addicted and needed more and more to get the effect. When he didn't get it, he went into withdrawl and became agitated and irritable, just like an addict.

Tabletop RPG

 * In Call of Cthulhu (tabletop game), Cthulhu Mythos spells and magic items grant the user great power, but inevitably lead to complete insanity and probable death.
 * Shadowrun:
 * The drug Kamikaze tremendously boosted your combat abilities, but each use permanently destroyed part of your body's ability to resist damage, and would eventually kill you.
 * Focus addiction. Magicians who used foci (spell-boosting magic items) too often became so dependent on them that they lost part of their natural magical ability and had to use the foci to cast magic at all.
 * Champions features the "Independent" limitation which can be placed on superpowers purchased through devices or magic items. The limitation effectively means that the points you spend on the power are separated from the character. If device or magic item is lost, stolen, or destroyed, the points the character invested in the object are gone forever and must be regained through Experience Points.

Video Games

 * In the Metroid Prime series, Phazon is a toxic substance that mutates and corrupts those it touches while giving them great power. It brings on many weaknesses such as draining life force and the possibility of a terminal corruption. The bad guys created many unstable freaks and mutants in their attempts to utilize Phazon as a weapon.
 * The PED suit in the third game, Corruption, allows the user (Samus) to use Phazon to her advantage without suffering immediate harm. However if you stay in the Super Mode that makes use of it for too long (approximately ten seconds of not using any attacks, the risk growing the longer it is turned on), you get a non-standard game over where Samus turns into a Dark Samus (or a copy thereof). You can be forced into it non voluntarily (if you're hit by a phazon based weapon or have the PED Suit hacked). Also, you use up health to use it (though the game is kind enough to return a percentage of your health used to start Hypermode if you manually disengage before it berserks).
 * You rely on your flashlight a lot in Alan Wake, since Dark Is Evil. In a few levels where you lose it, your only option is "run away really fast".

Visual Novels

 * in Yu No claims that without a certain pendant, she'll die. We later see her without it and she later clarifies that she meant it's as important to her as her life itself.

Web Comics

 * Cinema Bums features an evil Halloween wig in these strips, which Doug continues to wear after the holiday is over. Fortunately, he's Genre Savvy enough to remove it before it completely takes over.

Western Animation

 * In Gargoyles, the Archmage acquires three magic artifacts and uses them together to wield enormous power. When the Eye of Odin is.

Real Life

 * Modern civilization gets a large portion of its energy from oil, but keeping the supply flowing can be a challenge and vulnerable to enemy action, the supply is finite, and its use has ecological implications as well.