When you're meeting an alternate universe version/clone/zombie/etc. of someone, you're essentially dealing with a stranger. But because of your experience with your version, you may not feel that way.
For better or for worse, some people trigger very powerful emotional reactions in others. What specifically is being triggered varies — affection, protection, disgust, mistrust. However, it's very possible for the person triggering the response to be someone other than the person who originally provoked it.
Maybe the hero is meeting an alternate-universe counterpart to his dead little sister, who became his Cynicism Catalyst. Maybe he's reluctantly making himself team up with a good-aligned clone of his arch-nemesis. Maybe he's having to shoot one of his True Companions who has succumbed to The Virus and effectively stopped being the person he knew. Depending on the case, they may say You Remind Me of X. The point is that he's still having an emotional reaction to the person because of who they "are" — even though they aren't.
In some cases, this may not have any negative effects; the recipient is similar enough to the original target that it's still the correct reaction. However, sometimes (such as if the morality of the counterpart is inverted) things may not work out so well. This may also be used as a message against Expendable Clone - for Clones Are People, Too.
Replacement Goldfish is similar, but in those cases the individual getting the benefit (or detriment) of the character's previous relationship are not in any way the original themselves, though they may resemble them in some fashion. Also, this trope may last a shorter amount of time (for instance, if the hero meets the Alternate Universe version of his dead sister but then has to go back to his universe).
Evil Me Scares Me is sometimes played as an inversion — a hero seeing a villainous alternate version of himself may fear that his duplicate is him in some fashion and that he's really more evil than he likes to admit.
A subtrope of Psychological Projection; the person is projecting his feelings about his own version onto the other version. Related to Unbalanced by Rival's Kid (a person being angry at the child of a rival, particularly one who looks similar), Close to Home (a set of events or a person similar to an event that happened in the past complicates the present), Loving a Shadow and Doppelgänger Replacement Love Interest (a person falls in love with a duplicate of an old Love Interest), and Reincarnation Romance. It's also the reason why the Shapeshifter Guilt Trip is sometimes effective.
Compare Have We Met Yet? when you are meeting the same person, but they haven't met you from their perspective, so as far as they are concerned you're still a stranger.
- In InuYasha, the titular Inu-Yasha had great difficulty differentiating Kikyo from her reincarnation Kagome, often referring to the latter by the name of the woman he knew. Inu-Yasha also became greatly discomforted when Kagome dressed in traditional feudal Japan clothes as it made her further remind him of Kikyo, leading Inu-Yasha to tell her to put her own weird, modern clothes back on.
- In Yu-Gi-Oh!, the "Millennium World" arc has Yami Yugi/The Pharaoh get whisked into a world resembling his past life of Ancient Egypt. There he sees that his royal subjects are all past reincarnations of many people he knows in the present, and initially has trouble seeing them any differently. For instance, his chief adviser is Shimon and the doppelganger of Yugi's grandfather, who the Pharaoh still sees as a father figure, while Priest Seto still ended up becoming a worthy rival to him of sorts.
- Dragon Ball:
- Goku's reaction to fighting Copy-Vegeta seems to imply this. Even knowing this isn't really his rival, Goku just can't help enjoying the fight against this Vegeta. It helps that Copy-Vegeta completely absorbed the real Vegeta's power, personality, and memory, so Goku was pretty much fighting the real Vegeta colored purple.
- Vegeta seems to treat fighting Goku Black as another chance to beat on Kakarot, always eagerly snatching the chance to pound his rival's doppelganger.
- Detective Conan has an extremely unusual example. In "Murderer, Shinichi Kudo", in an attempt to frame Shinichi Kudo, a criminal underwent plastic surgery to take on Shinichi's likeness and then put himself into a murder situation to get Shinichi convicted. However what gives away the culprit's identity; in his home a smashed mirror was found. The reason for it? He had taken on the face of a man he hated and seeing that same face in the mirror led him to smash it in anger. This guy treated the doppelganger the same way he would to the real person when said doppelganger was himself.
- In the Darkwing Duck arc Crisis on Infinite Darkwings, Quiverwing Darkwing acts as an affectionate and somewhat mentorly figure to Gosalyn Prime. He used to have his own version of Gosalyn, who was his sidekick, but she died at some point prior to the arc (hence why he goes by her superhero identity).
- Subverted in The Multiversity: Pax Americana; after Captain Atom impulsively kills his dog in an effort to comprehend how it works, he then creates an exact replica, but can't bring himself to love it because he knows it's not the same dog.
- Secret Wars (2015): During the final incursion, which results in an Earth-Shattering Kaboom, Reed Richards watches as his family dies before they're able to get into the ark that can save them. The ark gets lost, with time standing still for everyone inside until it's later found eight years later. Upon emerging, Reed finds out that his archenemy Doctor Doom managed to save a small portion of reality with himself ruling as God-Emperor. As one of the many Take Thats Doom has orchestrated, in this new world, he is now married to Sue, with their children now also being Doom's. Though Reed is somewhat aware that this is a different Sue plucked from some random timeline/universe, it still hurts to watch her showing Doom her affection while having absolutely no idea who Reed is.
- X23 was abused by her creator because she was an Opposite-Sex Clone of Wolverine. He hated Wolverine because of his father's death related to the Weapon X project, and so X-23, grown from his DNA, made a good scapegoat for his frustrations with the other mutant.
- Acknowledged to various degrees in Exiles, which features various alternate heroes travelling through the multiverse; in their first mission as a team, they nearly failed in their mission because they assumed that the 'teacher' they had to help was the local Charles Xavier, only learning after they released him from prison that this version of Xavier was a villain. This twist led to the team's decision to make Blink- who originated from the Age of Apocalypse reality- to be the team leader, as she would be less likely to fall victim to this as her reality was so distant from the realities of the other members that she would likely have less of an attachment to the counterparts of the heroes-turned-villains they might face.
- An Interdimensional Meet: Featuring an original take on the The Flash/Supergirl crossover, this storyline includes Barry investingating the history of his counterpart on Kara's Earth and learning that, in this reality, he and his father were killed by Zoom while his mother survived. When Joe West comes to National City to investigate the apparent connection between the Allens' death and the city's new hero, Barry meets this world's version of his mother, with Nora immediately reacting to Barry as though he's still her son rather than an alternate version of him. When the storyline concludes, Nora accompanies Barry back to his Earth and is 'reunited' with Henry Allen, who acknowledges that they have technically never met but asks her out on a date nevertheless. When the story flash-forwards to a year later, Barry returns to Supergirl's Earth and reveals that Henry and Nora are now married- Nora using the name 'Grace' and posing as a distant relative of her counterpart- and he even has a new baby sister.
- Distorted Reflections features this quite often as SG-1 (Stargate SG-1) find themselves in a parallel universe where Earth has been decimated by a virus fifteen years ago (Jeremiah). Among particular examples, Jack O'Neill swiftly re-establishes his bond with the alternate version of the long-deceased Charles Kawalsky, Sam easily settles into a working relationship with Jack's own counterpart as well as dealing with her discomfort at meeting Martouf and Jolinar, and Daniel attempts to use his experience of Colonel Simmons in his world to manipulate the Simmons of this reality.
- In an interesting inversion of this trope, while Teal'c spends time working with Erin Gant, he finds himself reflecting that he must get to know Major Erin Gant when he returns to his reality, as Teal'c reflects how she, like Teal'c himself with Bra'tac and O'Neill, has put aside her own ambitions to serve a leader she respects in the form of Markus Alexander.
- In the Supernatural fanfic Mirror World, after Sam is abducted by the hunters of a parallel world and Dean and Castiel re-open the portal to save him, while Dean expresses disgust at what his father and himself have become in this reality, he eagerly hugs the alternate Bobby Singer even if he's consciously aware that this Bobby doesn't know him.
- Likewise, in Will the Real Dean Winchester Please Stand Up where Dean swaps places with his counterpart in another universe, while alt-Dean might at least partly agree to fight the current threat as it's the only way to get himself home rather than explicitly caring about his other self's associates, Dean clearly appreciates the chance to spend some time with his mother's living counterpart before he has to go home.
- In The Secret Return of Alex Mack, Alex spends time reminding herself not to fall victim to this when she initially meets her world's version of Jack O'Neill, even if he swiftly proves himself trustworthy, and this also contributes to her establishing a friendship with the 'local' Willow and Hermione.
- The Buffy the Vampire Slayer/Stargate SG-1 crossover An Extraordinary Journey acknowledges the SGC's usual philosophy of not worrying too much about alternate universes, but when circumstances send Willow to parallel universes she can't help but try and help her local counterparts, ranging from saving Dawn from a car accident to fighting her magic-corrupted alternate self, and everyone else in SG-1 feels her sorrow when she reveals that, in one reality she visited where there was never a Stargate Program, Jack O'Neill was Driven to Suicide by Charlie's death.
- The characters of My Little Pony: Equestria Girls are treated as the same as their Equestrian counterparts, the oddity of strangers inexplicably knowing about them quickly brushed aside. The exception to this is the human Twilight Sparkle in her first two appearances, with her being a Shrinking Violet that is reasonably unnerved by everyone acting as though they know her, with Sunset Shimmer blowing up on her for endangering her friends before later realizing she shouldn't have treated her as a simply copy of the other Twilight. This is continued in the next movie when Pony Twilight's Love Interest Flash Sentry starts crushing on her. She goes on to have a different love interest, while Sunset points out that this is a different Twilight and tells Flash that he should let go of his crush.
- Spider-Man: Into the Spider-Verse:
- When Peter B. and Aunt May first meet, they are briefly taken aback by each other's presence due to their respective versions having recently died. Aunt May quickly notes that she's aware he isn't related to her Peter at all before Peter B. can explain the situation, much to his surprise, but notes it is still nice to see some version of her nephew alive.
- Later on in the movie, Gwen tries to prevent this between Peter B. and the Mary Jane of Miles' dimension when the group are dressed as Spider-Man waiters. Peter B. ignores her and proceeds to profusely apologize for the circumstances that resulted in divorce back in his dimension, saying that she deserved a better man. Only to awkwardly claim that he was apologizing for his failure to restock the table with bread rolls when he realizes what he's doing.
- The One: Funsch and Roedecker are dimension-hopping Cowboy Cop and By-the-Book Cop partners; always bickering, etc. Soon after Roedecker is killed, Funsch meets Roedecker's counterpart, a storekeeper who has no idea what's going on. Funsch, despite knowing that this fellow isn't "his" Roedecker, gives him a heartfelt speech, thanking him for pulling him out of his Crapsack World and being a great partner and friend. An awesome way of saying goodbye.
- In the Stardoc novel Plague of Memory, Cherijo encounters what appears to be the reincarnation of her long-dead first husband Kao Torin, which understandably complicates her mission. It turns out to be a Hsktskt that was put through Magic Plastic Surgery using a DNA sample from Kao's corpse.
- Shota the witch woman from the Sword of Truth series first meets the protagonist while shapeshifted into his long dead mother. Though he isn't fooled, it's difficult for him to remain angry at her in that form.
- Still grieving over the death of Laurel Lance, Oliver is greatly affected by the appearance of her Evil Doppelgänger Black Siren. Despite his continual denial, it's apparent he sees her as the original Laurel and a second chance to save her.
- Detective Lance, Laurel's father, has a much stronger emotional reaction. In fact, he has an arc where he kidnaps her to try to convince her that she can be his daughter if they both believe hard enough.
- The Flash:
- This is how Team Flash reacted when Harry Wells from Earth-2 first made his presence known. Being the Alternate Self version of the man who Eobard Thawne was impersonating made it very difficult for Team Flash to trust him, despite Harry's constant reminders that he was not Thawne.
- Earth-3 Jay Garrick is the doppelganger of Barry Allen's father, Henry. Barry is visibly emotionally overcome trying to deal with someone who looks just like his recently murdered father. Jay later learns Barry's situation. He feels bad for Barry, but also reminds him that he is not Henry and wouldn't make a very good Replacement Goldfish.
- This also occurs with HR Wells from Earth-19, the third Wells to be a member of Team Flash. Despite the fact that he was incompetent and unintelligent compared to his predecessors, Team Flash still accepts him as a team member. As Cisco explains, the other Wells were geniuses who they depended on, while with HR it was the inverse. So after everything that Harrison Wells had done for them, Cisco wanted "to be there for Harrison Wells."
- In the Season 2 finale, Zoom was Dragged Off to Hell where he was subjected to a Fate Worse than Death, becoming Black Flash, a zombie-like speedster with no traces of the mind of his former self. However when Barry and Killer Frost encounter Black Flash they still call him by his old name, and in Barry's case is evidently still terrified of his former nemesis.
- In Legends of Tomorrow, the Earth-X version of Leonard Snart, Leo, is an unrelenting do-gooder hero, which is stomach turning for his Earth-1 partner in crime Mick. Leo sees Mick as a Replacement Goldfish to his late partner Mickey, trying to help him out of his alcoholism and make him a better person, but this only seeks to infuriate Mick.
- Crisis on Earth-X:
- The Earth-X Version of Prometheus is the doppelganger of Oliver's dead best friend, Tommy, who died while the two were still having a fallout over Oliver being a secret vigilante. Oliver deeply wants to believe in the capacity for someone with his friend's face to change, but Prometheus, who was raised an unrepentant Nazi, uses Oliver's nostalgia and love for his friend to mock and manipulate him before deploying a cyanide capsule that forces Oliver to helplessly watch his best friend die a second time.
- When the Earth-1 heroes get captured and sent to Earth-X for execution, Earth-X Quentin Lance expresses difficulty killing Oliver, the man with the face of the fuhrer. So he opts to have a bag put over Oliver's head to make the act easier for him.
- Earth-X Quentin Lance also appears to be sentimental when he sees Earth-1 Sara, the doppelganger of his late daughter. He asks why someone like her was being held captive, to which Sara explains she likes both men and women. Lance mentions how Sara was just like his daughter and adds that he expunged said filth from his bloodline, having shunned her for being bisexual.
- Doctor Who
- This is explored in the two-parter "The Rebel Flesh" and "The Almost People". The Doctor comes upon a factory where employers use "flesh avatars" for dangerous work. But trouble starts when the avatars or "gangers" become sentient and start protesting their individuality to their originals. The episodes explores if the gangers should be considered real or not, with the Doctor insisting they are while the factory workers believe they are not. The Doctor experiments this using his ganger, by switching his Identical Twin ID Tag and seeing if Amy (who knows the Doctor better than anyone else) could notice the change. Turns out she couldn't, proving the ganger and the Doctor were one and the same person.
- In "The Zygon Invasion", the shape-shifting Zygons specifically use this against the humans. When a squad of soldiers surround a church full of Zygons, one Zygon comes out taking the form of one of the soldier's mother, constantly pleading to him in a heartfelt way. The soldier cannot bring himself to kill what looks like his mother, and when other Zygons emerge as the loved ones of the other soldiers, they all agree to head into the church, where the Zygons promptly slaughter them. Furthermore, the Zygon commander, Bonnie, was impersonating Clara, which is implied to be one of the reasons why the Doctor was being very forgiving to her and wanted to help her pull a HeelFace Turn.
- The Outer Limits (1995), "Second Soul": A man's wife becomes a donor for an alien race that needs to possess dead humans to live. The alien is not happy about his persistent interest in her.
- Star Trek:
- Star Trek: The Original Series:
- In "What Are Little Girls Made Of?", when the android Kirk calls him an interfering half-breed, Spock visibly withdraws into his Vulcan shell. Given that he soon afterwards leads a security team to look for Kirk and Chapel, he realized immediately or soon thereafter that this couldn't be his Captain, but it still hurt to have a duplicate of his best friend target one of his major insecurities.
- In "Shore Leave", Kirk knows the "Ruth" and "Finnegan" he meets cannot be the real deals (for one thing, Finnegan hasn't aged since the Academy) but he still enjoys indulging his emotions with each of the duplicates (having a romantic time with Ruth and whaling on Finnegan).
- Implied in "Mirror, Mirror". Kirk shows more softness than one would expect toward the Mirror Spock, who (despite being better than Mirror Kirk) is as ruthless as one would expect from the Mirrorverse. This probably has something to do with his close relationship to his own Spock. Kirk even comments on how alike they are.
- Star Trek: The Next Generation: In the episode "Parallels" (where Worf encounters many alternate universes) the Primeverse Enterprise briefly receives a transmission from an alternate-universe version of Riker, now in command after Picard died during the events of "The Best of Both Worlds". He expresses his happiness to see Picard, saying that it's been a while.
- Star Trek: Deep Space Nine:
- Enforced in "Rejoined" as an allegory to closeted homosexuality. The episode has Jadzia Dax work with Lenara Kahn, another joined Trill. The Dax and Kahn symbionts were married in previous lifetimes, and the two women find that they're still strongly attracted to one another despite "reassociation" being a taboo in Trill culture. They ultimately do not stay together due to societal pressure.
- When Jake Sisko meets the Mirror Universe counterpart of his deceased mother, he treats her as if she really were his mother. In return, she starts to view him as the son she never had.
- Star Trek: The Original Series:
- Stargate SG-1: After hosting the Tok'ra symbiont Jolinar in "In the Line of Duty", Samantha Carter inherits some of Jolinar's memories, which includes a romantic attraction to the Tok'ra operative Martouf, lover of Jolinar's previous host Rosha. Also inverted: Jolinar's memories complicate Sam's preexisting Unresolved Sexual Tension with the Tollan diplomat Narim, with Sam telling him she's holding off on dating until she's more sure whether she's feeling things herself or because of Jolinar.
- Sam and Dean find themselves sucked into an Apocalyptic Earth-2. While there, they meet that Earth's version of Bobby. Earth-1 Bobby was their father figure and died suddenly and tragically so it shakes the brothers to see him alive on this Earth. However, because of choices made by their parents, Sam and Dean were never born on Earth-2, so he has no such attachment to them.
- Jack's mother dies giving birth to him, so he's always felt something was missing, having been able to communicate telepathically with his mother in utero but never getting to meet her face to face. While working a case, he and the brothers encounter a shapeshifter who works as a bereavement counselor. She is able to use the brothers' memories of Kelly to take her form and give Jack a chance to "speak" to the mother he was never able to meet. Jack is thrilled to finally be able to hug her and thank her for protecting him.
- Sword Art Online:
- In Hollow Fragment, the video game adaptation of the series, Kirito encounters a Hollow Data version of Sachi, his deceased first love who he failed to save. Although suspecting she's not real, Kirito is hellbent on protecting her at all costs so she won't die again. Eventually Sachi reveals she is indeed not the real Sachi. She also remembers the words the real Sachi never got to say to Kirito, which leaves him distraught and shaken, but also giving him closure.
- In Hollow Realization, Kirito and Asuna encounter Kizmel, a Dark Elf NPC with unusually-developed Artificial Intelligence they befriended back in Aincrad, only to discover this version of her is just a copy created by Sword Art Origin (the game itself uses many of the assets and data of the original SAO as a basis). Despite this, neither of them can bring themselves to treat her as just another NPC, further compounded by how this Kizmel seems to share the old one's strangely-developed AI, and grow to befriend her all over again. When Kizmel eventually sacrifices herself to save them from a petrifying curse, they chose to use an item necessary for their current quest to revive her and eventually they recruit her into their group to have more adventures.
- Accel World VS Sword Art Online: Millennium Twilight, due to the time travel shenanigans of the game and the fact the game continuity is an Alternate Timeline to the canon continuity, Kirito ends up meeting a version of Eugeo from another timeline (who is implied to be the canon version). Upon seeing Kirito, Eugeo mistakes him for his Kirito and tries to get him to remember, only to be disappointed that this Kirito has no memories of their time togethernote . However after having a friendly duel with Kirito to test him, Eugeo realizes that while this is a different Kirito, it is still Kirito who fights the exact same way. He then takes up on Kirito's offer to hang out and party with him until he's able to return to his own timeline.
- The Witcher 3 features the doppeler Du-Du who can take on the form of anyone he pleases. In a time where anything not 100% mundane can lead to being burned at the stake, Du-Du tends to mimic people who are either very esteemed or very feared. This nearly gets him killed when he chooses to shapeshift Whoreson jr, one of the city's underbosses. Ciri, a ridiculously overpowered half-elf, and her father-figure, protagonist and renowned witcher, Geralt, nearly murder him as Whoreson, Jr. tried to kill Ciri the last time the two crossed paths. Du-Du is forced to reveal his true form to avoid being murdered by his own friends.
- In Life Is Strange, Max Caulfield creates an alternate universe when she prevents the father of her best friend, Chloe Price, from dying in a car accident. The Butterfly Effect leads to Alternate!Chloe getting into a car accident herself; it leaves her paralyzed and under constant supervision. Alt!Max hadn't seen Alt!Chloe in years due to a move to Seattle, but the original Max had the benefit of having begun to catch up with her Chloe—she was nearly unable to make a choice when Alt!Chloe, realizing that her parents had paid millions of dollars for her upkeep, requested that Max help her kill herself with a morphine overdose.
- Fate/Grand Order:
- Kingu impersonates Gilgamesh's deceased friend Enkidu to gain his trust as part of Tiamat's plan to destroy him. When Gilgamesh finds out, he decides to give him a chance as he looks like Enkidu. His faith pays off, as Kingu is eventually touched enough to turn against Tiamat and sacrifice himself to stop her. Gilgamesh is heartbroken to have to watch his best friend die a second time.
- Assassin EMIYA is an alternate version of Kiritsugu Emiya who never had a family. Irisviel, Illyasviel, and Archer EMIYA still treat him as their husband and father, which annoys him as he doesn't know them.
- Fire Emblem Awakening uses this as one of its main emotional plot points. When Lucina and the other children, refugees from an alternate universe Bad Future, meet their "parents" in the game's home universe, many of the children can't help but treat them the same as their actual, now-dead parents. Some are more resistant, but because of the game's general adherence to The Power of Love, all of them end up accepting their newfound family.
- In Homestuck, Dave spend much of the Intermission being very anxious/nervous about meeting Dirk, an alternate universe version of his "older brother" who raised him. His nervousness reflects his insecurity and fear towards his enigmatic and abusive "older brother", and Dave harbors similar feelings towards the alternate universe version, even though he is the same age as Dave and has none of the same history. When they ultimately meet, Dave uses Dirk to work out his issues with the older version, specifically his use of irony to pretend that he wasn't in a deeply unhealthy relationship.
- In El Goonish Shive, Tedd thinks of Ellen the same way he thinks of Elliot: as a friend he's known since childhood. Ellen makes it clear she doesn't feel quite the same way.
- In the Darkwing Duck episode "Life, the Negaverse, and Everything", Darkwing finds himself in an alternate universe. He immediately becomes as fiercely protective of Nega-Gosalyn as he is of his own.
- In Justice League, the Justice Lord version of Batman panics when Flash fakes flatlining by speeding up his heart rate, because the Justice Lord universe's version of Flash was killed by Lex Luthor.
- In Phineas and Ferb The Movie: Across the 2nd Dimension, the Phineas and Ferb from the second dimension get really excited to see the first dimension's Perry, hugging him for a few more seconds even after finding out he's not their Perry, who'd disappeared ages ago.
- A large part of the shock value in Playing Against Type relies on the audience's familiarity with the other characters the actor has played.