Of all the ways that First Contact can happen, you'd think that one of the happiest would be members of one species rescuing and healing a member of a different species who had a nasty accident on their territory. It establishes that the hosts are altruistic and don't want to conquer/destroy/eat the guests, and it ensures that the guest and their people should be suitably grateful. Unfortunately, there's one big pitfall.
Even if you have super-advanced healing techniques, you may not know precisely what the endpoint for an unfamiliar entity should be. OK, you can reattach all those severed bits, but how do you know which stump they were chopped off?
This trope occurs when somebody who was rescued and healed by Starfish Aliens ends up looking like a Body Horror parody of themselves because the aliens came to the wrong conclusions about what they were trying to rebuild.
Obviously, this can happen with humans attempting to heal aliens as well, and with entities of whatever sort attempting to repair machines, if the machine is fully sentient.
A particularly unfortunate version of Humans Through Alien Eyes. See also Comically Inept Healing when played for laughs. If the healer knew what they were doing but deliberately experimented For Science! or perverted fun, see Mad Doctor. If they knew what they were doing but didn't have the time or equipment to do a proper job, see Meatgrinder Surgery.
- The Yuri Genre series Kashimashi: Girl Meets Girl's premise is that the Bishōnen lead character, Hazumu, was accidentally mortally wounded when a UFO crashed on top of him, and the aliens, trying to make amends but unfamiliar with human anatomy, recreated him with a female body.
- Vandread: Played for laughs with the character of Duello, a Tarak medic who is generally very good at his job. However, since Tarak has no women on it whatsoever, he's ignorant of female anatomy and is terribly confused when he tries to treat a woman who is pregnant, instead diagnosing her with an "abdominal parasite". He's later no help at all when the woman goes into labor, since the birthing process is something he's never seen before.
- Inverted example in the BBC Books Doctor Who Graphic Novels installment The Dalek Project; human archaeologists reconstruct a damaged Dalek and mix up all of its different structural parts and appendages, although it's still able to try to kill them.
- In Joe Simon's bizarre and short-lived (only one issue) 1970s DC team book The Outsiders (not to be confused with the later Batman-led covert team of the same name), the team leader "Doc Scary" was disfigured by not-quite-humanoid-enough aliens who reconstructed his face after a spaceship crash to look like one of them.
- Superboy and the Ravers: Byron Stark was horrifically injured when an alien craft crashed into his parent's house back in the 1950s and the ship's subsequent attempts to repair him replaced his damaged flesh with transparent green goo and stopped him from aging any further. The green stuff "repairs" any injuries he suffers afterwards in the same way making him understandably protective of his remaining human flesh.
- The collection The Indispensable Calvin and Hobbes features a poem in which Calvin imagines his bones being found and erroneously reconstructed by aliens.
What if my bones were in a museum
Where aliens paid good money to see 'em?
And suppose that they'd put me together all wrong,
Sticking bones onto bones where they didn't belong?
Imagine phalanges, pelvis and spine
Welded to mandibles that once had been mine!
With each missassemblage, the error compounded,
The aliens would draw back in terror, astounded!
Their textbooks would show me in grim illustration,
The most hideous thing ever seen in creation!
The museum would commission a model in plaster
Of ME, to be called, "Evolution's Disaster"!
- Averted in *batteries not included when handyman Harry Noble takes it upon himself to repair a stillborn baby Fix-It, a species of living machines that look like little flying saucers with eyes. It takes a hell of a lot of tinkering and false starts, but eventually he gets it functional and (reluctantly) returns it to its parents.
- In Star Trek: The Motion Picture the terrifying entity V'Ger turns out to be a twentieth-century human Voyager space probe, reconstructed by a culture of AIs who decided to "help" it in its mission by making it more powerful, leading to it becoming a threat to humanity.
- In the Imperial Radch series, the Starfish Alien Presger grew Artificial Human "Translators" from human remains to act as intermediaries with the Radch. While their early efforts are left unseen, it's mentioned that the Presger had a decent practical understanding of how humans are put together — mostly from taking them apart for fun — but didn't quite know "what was important." Through trial and error, they managed to produce Translators that look human (most of the time) and are only mentally in the Uncanny Valley.
- In Alan Dean Foster's Sentenced To Prism, the main protagonist, Even Orgell, as well as the person he's searching for, have both been seriously injured and are repaired by the native lifeforms. Which are mostly silicon-based and photovores, rather than carbon-based. Orgell ends up with what's basically a lithium battery in place of his heart, and a chemical fuel cell in place of his stomach; when he finds the woman he's searching for, she's had the long bones of one arm replaced with a laser array and she has shoulder-length glass-fiber hair.
- Doctor Who:
- In the TV Movie, the Seventh Doctor falls victim to this after being shot, as he gets brought to the hospital and the doctors, not knowing he's not human, wind up accidentally killing him on the operating table. Due to the anesthetic, he doesn't regenerate into Eight for a few hours, and ends up Waking Up at the Morgue.
- The "gas-mask zombie" plague in "The Empty Child"/"The Doctor Dances" was caused by escaped alien medical nanobots who were trying to heal people. The first human they found was a young boy wearing a gas mask who'd recently been killed by a bomb, and they didn't realize that gas masks weren't a normal part of the human anatomy. So when they started "fixing" humans, they gave them all gas masks and the same injuries the boy had, such as a collapsed chest cavity and a scar on the back of the right hand. The Doctor solves the problem by providing the nanobots with an actual template of what a healthy human looks like, causing them to reverse their work and heal everyone.
- A comedic example in Farscape had Crais and Jool tasked with putting back together an alien capable of surviving its current scattered state. Crais picks up what he believes to be its head, but Jool points out that if it were the case, the alien would be sitting on his head. Much to their despair, the alien gets killed just as they had managed to get it conscious and capable of talking.
- In the unbroadcast Star Trek: The Original Series pilot "The Cage", and the two-part story it was expanded and re-edited into "The Menagerie", the apparently beautiful Vina was actually disfigured and disabled by Sufficiently Advanced Aliens who healed her after a starship crash without knowing what they were doing.
- Mega Man 8: The alien robot Duo crash lands on earth and is heavily damaged; Mega Man brings him to Doctor Light for reparation. As he doesn't fully understand Duo's systems, Duo ended up becoming different from what he used to be and somewhat weaker but still phenomenally strong.
- In Awful Hospital, this is a hazard of the archetypal Hospital, which processes entities from all across The Multiverse who get sick in ways that their native realities can't handle. The protagonist is forced to avoid doctors who might not even know how to treat beings made of matter. The Parliament's ongoing attack on the concepts of sickness and health that sustain the Hospital don't help matters either.
Dr. Man: I'm afraid [the staff] simply wouldn't know one of our flu vaccines from a needle full of mercury. Can't blame them, really; that's precisely what works for a Vogooz or any patient out of the quasi-acoustic zones.
- Whateley Universe: This trope results in a Gender Bender in Cosmic Plaything Josie Gilman's Superhero Origin story: Josh suffers a groin injury, and is healed by the Raised by Wolves Nightmare Fuel Station Attendant Ecila Mason, but since she was too young to understand the difference between boys and girls when she left humanity behind, she removes the "parasite" between his legs. This later turns out to be a Red Herring, as it is determined that Josh had already begun to transform into Josie even before then.
- Buzz Lightyear of Star Command XR the robot is who he is because the little green men were off their group mind when they rebuilt him.
- Dr. Zoidberg in Futurama has next to no knowledge of human anatomy (the anatomy chart on his office is hung upside-down), so naturally his attempts at surgery usually go horribly wrong. Examples include mixing up Fry's arm and leg (after he himself cut them off during a Blood Sport in his native planet) and mutilating the entire crew (including Bender, a freaking robot!) in an attempt to cure a simple case of jaundice. It's only through unspecified advances in 30th Century medical technology that none of his failures turn out to be lethal or irreversible.
- The episode "The Ambergris Element" from Star Trek: The Animated Series by Filmation Associates has Captain Kirk and First Officer Spock visit the watery planet Argo. There, they are captured by a giant marine monster, and a second team is dispatched to rescue them. When the two senior officers are found, both have been fitted with gills and webbing between their fingers, and can no longer survive out of the water. The Aquans that inhabit Argo are xenophobic, especially of air-breathers, but took pity on Kirk and Spock, restructuring them to survive in a marine environment. Much of the episode revolves around efforts to undo this process.
- The closest real-life equivalent often happens when paleontologists try to reconstruct prehistoric organisms from fragmentary or distorted fossils, leading to incorrect representations. Famously, the first reconstructions of Iguanodons had big horns on their snouts before more complete skeletons were found that showed the spikes served as thumbs.