Your Heart's Desire

"We can supply anything

That your heart desires

But the consequences

Will surely be dire!"

- Creature Feature, "The Greatest Show Unearthed"

Some monsters ensnare you by taking the shape of your worst fears, knowing your deepest nightmares and using them against you. These can be some of the most terrifying enemies, attacking you where you are most vulnerable in the dark recesses of your heart. But sometimes the thing that's the most scary isn't the monster that attacks you with fear.

It's these guys.

These badguys trap you by preying upon your desires. They know what you want and are willing to offer it to you - or so it would seem. They show you things you've always dreamed of, presenting you with the very thing that your heart yearns for. However, Be Careful What You Wish For. Temptation can be a powerful and dangerous thing, and is sometimes harder to resist than any overt danger.

This is a favorite technique of the Master of Illusion, who may use it to trap others in a Lotus Eater Machine, or the kinds of monsters that get satisfaction out of manipulating their victims' emotions. After all, it's much easier to catch flies with honey than with vinegar, and the victim often won't even be able to realize the danger until it's too late. This is why your parents always told you not to take candy from strangers.

Anime and Manga

 * In Nabari no Ou, the Shinrabanshou often tries to tempt Miharu into telling her his greatest desires, and then she will grant him her destructive power, regardless of whether his body can handle it.

Comic Books

 * In For the Man Who Has Everything a Lotus Eater Machine of this sort is used on Superman, who hallucinates that he's back on Krypton.
 * Rare hero example: Danielle Moonstar, AKA Mirage of the New Mutants, could create a mental illusion of your worst fear, or your heart's desire. She could choose which one, but even she couldn't know what her victim was seeing.
 * The X-Men annual Lost in the Funhouse revolved around this - Horde, the villain of the issue, sent the team to a Citadel to retrieve a MacGuffin on pain of destroying their world if they refused. The citadel's defence mechanism was offering intruders a vision of their heart's desire one-by-one. When it couldn't find Longshot's desire due to his "purity", it cut out step two and absorbed him.

Literature

 * In the novel Something Wicked This Way Comes by Ray Bradbury, the carnival tries to entice the boys by showing them exciting and marvelous things. Particularly Jim, who is fascinated by it, and who also has a desire to become older.
 * Stanley G. Weinbaum's science fiction short story "A Martian Odyssey" had a carnivorous plant monster that read the mind of its victim and created a mental illusion of what the victim most desired to lure it into the plant's clutches.
 * The short story "A Part of the Game" in Dragon magazine #51. A group of desert travelers find an oasis which appears to be a gate to a utopian other world. Most of the group enters the pool only to be eaten by its inhabitant, a monster that can create beautiful illusions.
 * Harry Potter had the Mirror of Erised, which shows the viewer whatever their greatest desire is. Ron, who feels overshadowed by his siblings, sees himself outdoing them all. Harry, who never knew his real family, sees himself with his parents and relatives. Dumbledore mentions that it can be highly addictive, however.
 * Primary modus operandi of the Denarians in The Dresden Files.

Live Action TV

 * Red Dwarf: Back to Earth has a joy squid (opposite of the despair squid in earlier episodes.) Both had the same effect of trapping you in a hallucination until you die.

Mythology

 * This goes all the way back to the Sirens of Greek Mythology. They would sing a song that made them irresistible to sailors, who would steer their ships toward the sound. Then the ships would hit the rocks surrounding the sirens and sink.
 * In a great many stories Satan is said to know Your Heart's Desire in order to get you to sign a Deal With the Devil. Far too many stories to list, really.
 * Several examples of Jackass Genie.

Newspaper Comics

 * Lil Abner: On August 31, 1948, cartoonist Al Capp introduced the schmoo, a bewhiskered white blob of a creature that looked like a bowling pin with legs. Schmoos seemed to exist only to provide humanity with its every need. Capp said he came up with the idea of the schmoo when he was driving through the New England countryside and saw the abundance that the earth provided. People of all political stripes -- communists and capitalists alike -- saw the schmoos as an analogy critical of their beliefs. (The fact that "schmoos" rhymes with "schmooze" didn't help.) Schmoos were Explosive Breeders that laid eggs and could give milk. If they really loved you, they'd could lay a cheesecake. And if you expressed a desire to eat a schmoo, one of them would die of ecstasy just to provide you with the opportunity. Naturally, a schmoo Tastes Like Chicken. Fed up with all the controversy over a character he claimed was nothing more than a commentary on the abundance of nature, Capp carried out a Writer Revolt by slaughtering the entire species in December. The Other Wiki has a more detailed analysis of the schmoos here.

Tabletop RPG

 * Dungeons and Dragons
 * 1st/2nd Edition
 * Adventure S4 The Lost Caverns of Tsojcanth. A group of dao (similar to djinn) create an illusion of a desirable setting to lure the party into a cave. When the party enters, the dao attack.
 * Dark Sun/World of Athas campaign setting. The Red Silt Horror uses its telepathic/ESP abilities to determine what its target desires most, then uses its False Sensory Input power to create an image of the desired item. After its target moves close to it, it attacks.
 * Forgotten Realms supplement FR4 The Magister. The Cloak of Delight can cause any creature that sees it to fall into an motionless and oblivious trance for 1-8 minutes by showing the creature its ultimate pleasure and goal. The creature will maniacally attack any creature or thing that blocks its view of the Cloak. If its view is blocked by something without solid form (e.g. darkness or smoke) the trance ends.
 * 3rd Edition. Creature Collection supplement. The Dweller at the Crossroads is a sinister figure that knows its victim's greatest wish and can grant it - for a price. Every gift the dweller gives is cursed in some way to bring corruption and misery to the person receiving it.
 * Shadowrun had an Awakened creature ability called "Desire Reflection" that was basically this. Only a few magical creatures possessed it.
 * Paranormal Animals of North America: Incubus
 * Paranormal Animals of Europe: Blackberry Cat, Kludde
 * Critters: Quicksilver Mongoose, Siberian Firebird
 * Neverwhere RPG. The angel Islington could see into people’s hearts and offer them what they most desired.
 * Subverted in the Gamescience's Space Patrol RPG. In an example of play a man walking through a forest sees a beautiful nude woman. Believing that such coincidence is only possible in the movies, he decides that the woman is an illusion created by a man-hungry alien monster. He draws his blaster and fires at it, reducing it to its component atoms. The text reveals that the man was wrong: it was a real woman and he is now a murderer.

Video Games

 * Pretty much the reason people enter into Twisted Metal.
 * The PC horror game The Path can be interpreted this way, as it seems that  is something that appeals to them according to their personality, and thus they are lured in one by one.
 * The aptly-named Desire Demons from Dragon Age

Western Animation

 * The Series of Aladdin had a variant in one episode: a small, timid animal that can do this whenever scared, hoping to distract a perceived threat. Naturally, Iago and Abu continually frighten it just to get stuff.