Twinmaker

"The machine, in fact, merely analyzed the contents of the first booth, then sent a description of it to the second booth, where a copy was created. The contents of the first booth were then destroyed."

- To Be

The concept of clones or copies being made to replace original people, usually either as a means of Teleportation (by creating a copy somewhere else and destroying the original) or as a way of obtaining Immortality (creating clones to replace a dying or dead original, for example).

The Twin Maker is often a convenient way of bringing a dead character back from the dead without needing to invoke any trope that revives the old character. In manner and appearance, they are almost always perfect doppelgangers, indistinguishable from the original. This trope is often used in a science-fiction setting, where it can be readily justified by any amount of technobabble on cloning, teleportation devices, copying machines, and the like. Fantasy and other works involving magic are also natural habitats for this trope. When an original is not dead yet, there may be some interaction between them and their clone, but usually it's a case of Never the Selves Shall Meet.

Where this trope gets interesting is how the moral status of the new copy and the moral implications of disposing of the original are handled. First, the treatment of the twin: Some characters won't see the problem with treating them both as if they were the same person, whereas others will point out that it only works from an external viewpoint: the person will seem exactly the same to everyone else, but the actual stream of consciousness has been severed, and the new copy is, in this sense, a completely different person. Sometimes it will be argued that the copy doesn't count as the original person, though given how interchangeable they would be if the paperwork for their birth certificates were ever mixed up, this argument is harder to hold up for long.

Second, the ethics of disposing of the original: If this matter is addressed at all in fiction, the Uniqueness Value and Cloning Blues tropes may well be invoked or played with as part of the story. A teleportation machine that worked in the manner of the short story To Be (see quotation above) would probably be regarded as a killing machine, but if there is any doubt about whether the stream-of-consciousness continues or not, the issue may well be sidestepped. If nothing in the device suggests anything sinister, it's generally treated as harmless. It's probably a straightforward Teleportation.

If the Twinmaker is kept a secret, it will probably be part of The Reveal. Particularly devious characters may exploit the Twinmaker for their own ends, perhaps to create decoys to lure out assassins, or to dispose of an Unwitting Pawn by "tweaking" it mid-way through its creation.

Often involves Cloning Blues. Clone Jesus and You Cloned Hitler are related, but not subtropes.

Anime & Manga

 * in Neon Genesis Evangelion actually appears as three different clones over the course of the show. This isn't known until The Reveal.
 * Furthermore, a Freeze-Frame Bonus reveals that the lower half of Lilith is actually
 * of Magical Girl Lyrical Nanoha was developed as a Replacement Goldfish shortly after the originals' death. It didn't go exactly as planned, and her creator wasn't thrilled.

Film

 * In the live-action In Name Only Aeon Flux movie, . Only a select few Ancient Keepers are permitted to know this.
 * Alien: Resurrection is about scientists trying to do this to, who dies in the third film.
 * In The Prestige,
 * The first time this happens, . (Then again, the concept of "the original" isn't well-defined, given what we know about quantum physics.)
 * The first time this happens, . (Then again, the concept of "the original" isn't well-defined, given what we know about quantum physics.)

Literature
""I'm embodied, not deranged! If a copy of my mind experiences a few minutes' consciousness, then is lost, that's not the death of anyone. It's just amnesia.""
 * The trope namer is Resurrected Man, where "Murdering Twinmaker" is both a nickname for the teleporter and the nickname for a serial killer who uses the data in the sending teleporter to create his own copies, which he murders for pleasure.
 * Orson Scott Card's short story "Fat Farm": People can be cloned and have their memories copied into the clone. The clone then replaces the original person.
 * Miles Vorkosigian has one of these in the Vorkosigan Saga. He was created to replace Miles, but when Miles and his family found out they broke the clone out and adopted it into the family. He's treated by everyone as Miles' brother.
 * The C. J. Cherryh novel Cyteen, explored the difficulties of using cloning to make an exact duplicate. In order to produce a clone genius on par with the original the scientists raising the clone had to duplicate the original's upbringing as closely as possible.
 * The title character of Joshua, Son of None is a clone of JFK, whose upbringing and experiences are "managed" in a similar manner by his creators. The plan starts to go off the rails when he discovers this.
 * In some of Greg Egan's stories, characters deal with things by imagining a line of continuity from the death of the first copy to the creation of the second, despite the lack of causal connection; this shows up in Permutation City and in Schild's Ladder, and possibly elsewhere.


 * In Permutation City,
 * In the short story "The Extra",.
 * Sam Vimes objects to using magic anyway, but in Thud!, even when he gives in and goes to the wizards for help, he absolutely refuses to use teleportation because he's paranoid about the idea that the person at the other end isn't the same person as the one who was teleported.
 * In James Patrick Kelly's novelette "Think Like a Dinosaur", reptilian aliens give us teleportation, but insist on "balancing the equation" (destroying the original afterward) or they'll cut us off from the network. Normally the original is unconscious, but one is revived after the teleport is mistakenly believed to have failed, invoking this trope in full.
 * In the Star Trek Expanded Universe novel Federation, when Zefram Cochrane is first transported aboard the Enterprise, he immediately thinks he is a duplicate of the original, assuming transporters to work like replicators. Instead, a crew member calms him down, explaning that the process works on the quantum level, meaning he is still the original Cochrane.
 * Averted in Sergey Lukyanenko's Line of Delirium, where the aTan machine re-creates people after their deaths by replicating their bodies from the previous molecular scan and downloading the stored memories into the new brains. Originally, it is claimed by the aTan Corporation that each re-created person is indeed new, although they are considered to be the heir to the dead person's life. However, it is revealed later that re-creating the same person twice only results in one having a consciousness, while the other is a mindless zombie, only able to passively answer questions and perform routine tasks. This is due to something the aTan people call the "x-factor" that is present in humans and several other races. When a person dies and his or her body is re-created by aTan, this "x-factor" locates the new body and inhabits it, giving this new body the same consciousness as the dead person. For some reason, the aTan Corporation decides to keep this a secret from the general public, only informing the Church of the One Will of their findings. Needless to say, the Patriarch immediately gives full blessing to aTan. After all, it's not every day that someone proves the existence of the soul.
 * China Mieville's novel Kraken has a nasty subplot based on this idea, about an Urban Fantasy magician who developes a teleportation spell consciously inspired by Star Trek transporters. He doesn't realise that the method actually kills the original and creates an unaware, perfect copy until the vengeful spirits of his dead former versions start haunting him.
 * The Goblin Reservation is built around this trope.
 * In The End of Eternity, the eponymous organization considers replicators as undesirable as nuclear wars - because there can be no satisfactory solution to the problems caused by this trope.

Live-Action Television

 * Farscape had a subplot of Crichton's twinning. Although in this case, neither one was a copy or original exactly. Crichton really was just duplicated/"twinned" into two identical Crichtons (they play rock-paper-scissors and draw some 100+ in a row).
 * They even use this in the next episode to have one twin impersonate the other to "prove" Crichton was never at the scene of an explosion (since he is of course, completely unhurt).
 * The rock-paper-scissors thing is referenced later to show how they have diverged from each other, one (having died) sends the other a holographic recording which he closes by offering to play again, throwing rock as the other Crichton throws paper.
 * Star Trek: The Next Generation had Thomas Riker, William T. Riker's transporter duplicate, created during a pre-show mission when someone tried doubling up the transporter-lock to get a better chance of beaming him off a planet with tons of interference during an emergency. One transport-beam made it to the ship, the other got bounced back to the surface. Nobody realized at the time that they had created two Rikers, one of which was marooned for years as the other advanced his career and went on living his life. Interestingly, Thomas claimed that he would never leave Deanna, as Will has done, even though up until the split they were the same person. This was probably Thomas trying to distance himself from Will, hating that he chose to advance his career instead of maintaining his relationship with Deanna. Also interesting in that technically both Rikers are copies of the original who first went through the transporter due to the way the transporter works, so neither is technically any less real than the other.
 * Star Trek: Deep Space Nine: Weyoun has died and been replaced with a clone several times over the course of the series. One episode dealt with two Weyoun clones existing at the same time (one had gone AWOL, so his next clone was activated early). Near the end of the series, he's deeply frightened when the Dominion's cloning facility is destroyed, allowing him to be Killed Off for Real.
 * The Outer Limits made "Think Like a Dinosaur" (see Literature) section into an episode.
 * In an episode of Earth: Final Conflict, Liam is implanted with a tracking device by Sandoval at Zo'or's request, as they have grown suspicious of him. In order to allow them to continue their investigation and keep Sandoval and Zo'or in the dark, Street puts Liam into a mini-coma and uses a modified ID portal to create a quantum duplicate of him without the tracking device, although she claims that the universe will eventually erase him out of existence. The duplicate Liam is identical to the original in every way and doesn't seem to mind being the copy. At the end of the episode, he makes a Heroic Sacrifice to save Renee. Just before the Earthshattering Kaboom, he sends a message to Sandoval, which confuses the latter to no end, as he knows thanks to the tracking chip that Liam is nowhere near that location. He later questions the real Liam, who has no memories of these events, before dismissing the matter.
 * Like many devices introduced in the series, this Twinmaker is never mentioned again, even though it would have been very helpful in many other circumstances.

Tabletop RPG

 * Paranoia: Every player character has six identical clones, and when one dies, the next one is sent in to replace it.
 * In Dungeons and Dragons Clone spell could be used to create copies of a creature, normally as a form of resurrection when the original is lost completely. Only One Me Allowed Right Now effects implied that it's more than just an identical body, though. Stasis Clone (unique spell from Forgotten Realms) makes the revival of one stored copy upon death automatic and allows to "update" inactive clones.
 * As of 3E the Clone spell simply creates an inert duplicate that the original's soul transfers to at death.
 * Eclipse Phase uses Brain Uploading for both pseudo-immortality and most interplanetary "travel". Though unless they were really rich someone rarely gets downloaded into a clone, rather a "used morph" that happened to be lying around at the body bank. Making more than one active copy of a person is fairly easy and highly illegal, but slightly edited copies are sometimes used for a form of real-time interplanetary communication.

Video Games

 * Tales of the Abyss.
 * Shadow from Sonic the Hedgehog was revealed to be possibly a clone of the one from Sonic Adventure 2 at the end of Sonic Heroes. The other two members of Team Dark discovers a lab full clones in tubes, and destroy them all without telling him. Rouge reveals she knew he was a copy the entire time. This being the first game after Sega went third-party, the writing hadn't completely started to suck yet.
 * Of course, this was all retconned in Shadow the Hedgehog with the explanation that Eggman had sent a robot to recover his body after he visibly burned to death falling to earth from an orbiting space station. Yeah.
 * The "Immortality Through Cloning" version is used as a plot point and gameplay mechanic in Destroy All Humans!. The reason the Furons are harvesting human brains is because it contains a strain of DNA vital to their cloning process, and every time you die in-game, your name increases by one digit. There's even a level about recovering your own remains.
 * In the Star Trek Armada games, Nebula-class ships have a special ability called the "Gemini Effect", which temporarily creates a duplicate of the target ship. With some quick thinking, this ability can be used to get free resources by duplicating a vessel and then scrapping the duplicate for parts. The game designers, apparently, did not think of this possibility.

Web Comics

 * In Freefall robots don't care much about backups. Want to know why?
 * While actual teleportation is possible in Schlock Mercenary, the wormgate network used for it prior to the invention of the teraport also created clones of those who used it without the traveler's knowledge.
 * Similarly, later on

Web Original

 * In the Mortasheen universe, Wreathe uses portal technology, which preserves the teleported person intact but is incredibly inefficient. Meanwhile Mortasheen utilizes teleportation that makes a twin of the user somewhere else and destroys the original. Mortasheen being what it is, no one there is bothered by this and the twin is considered and treated as the original. Wreathe, however, is revolted.

Western Animation

 * Canadian animator John Weldon's terrifying short, To Be: In it, a scientist is demonstrating his new "Murdering Twinmaker"-style teleporter. The heroine claims that the machine is immoral, and to assure her that there's no need to worry, he agrees to delay the "murdering" part of the machine by a few minutes. The original and the clone come out and meet each other, they play a game of chess, and then each fights tooth and nail to push the other into the machine. She just grabs one of them and helps the other scientist push him in as he kicks and screams and begs for his life. They end up shutting him in with his arm slammed in the door and nuking him, causing his arm to visibly disintegrate. Then it gets quiet. The surviving scientist realizes the immorality of such a device and walks away, but the heroine feels guilty and decides that she has to atone for what she does, and enters the machine.
 * In one Aeon Flux episode, the titular character's archenemy and lover creates a clone of her. The clone and the original meet and conspire against him. In the end, one of them gets gunned down in front of Trevor.
 * have this kind of immortality in The Venture Bros., but they're unaware of it. As of Season 3, when the clones were used as an army during an attack on the Venture compound, this is no longer true.