Bob is a common person living with us, with a normal childhood and adolescence, a job and a family. But then something happens. A wild event appears and reveals Bob was a human alien all along. May or may not gain powers with the reveal, but something is sure: he never was from Earth. Bob could be raised as a normal child, but his origins are not from this planet.
This trope is about the discovery of a character he/she wasn't from this planet, maybe is a Human Alien who wasn't aware of its origins until grownup, or maybe a creature who Was Once a Man until the reveal that this is his original form instead of being mutated. Since Tropes Are Flexible, inversions are also allowed, in this case, a human alien who discovered he was a normal human all the time, or at least not an alien.
Sub-trope of Tomato in the Mirror, which is also about discovering that you're not what you think you are. Inversion of Human All Along, even when not always is an alien as here. Compare Not of This Earth, an object or substance that's discovered that's not from this planet. See also Beethoven Was an Alien Spy and Raised by Humans. Not to be confused with Changeling Tale, which in this case, the human Bob is replaced for an alien Bob at birth.
- Son Goku from Dragon Ball was a boy with a big strength and a strange monkey tail, but apart of that he always thought he was a human as all the people he knew. That, until he was an adult (and a father), when he got the discovery that he was an alien all the time, an almost extinguished race called the "Saiyans", who were powerful savage warriors who conquered planets and he's one of the last survivors in the universe when his native planet exploded.
- Near the end of Rolling Girls, Chiaya finds out that she and her mother are actually aliens, which is why she sometimes turns into a small octopus-like creature.
- In general the origins of Superman, as well most of his Multiverse counterparts, are about discovering he was a Human Alien from the planet Krypton when he was an adult or a teenager. Usually their powers were discovered before his origin story, but in the case of one of his counterparts (Superboy-Prime), the discovery came at the same time with the powers, activated during the First Crisis.
- An inversion occurs in the Elseworld Superman: Last Son of Earth, in which the human baby Clark Kent crashes on the planet Krypton and was adopted by Jor-El and renamed as Kal-El, later becoming the Green Lantern of his planet and sector, and recovering his memories from the Earth.
- In Runaways, Karolina is the daughter of aliens from Majesdane, a fact that she only learns after finding out that they are murderers.
- Voodoo from Wild CATS was an exotic dancer saved by the Wild CATS who has the "gift" of knowing who was possessed by a Daemonite and who is not, also splitting the alien from the host. After joining the team and got in a coma by a bullet, she and his friends discovered the truth: she was a descendant of Daemonites with Kherubin roots.
- Played With Marvel's Crisis Crossover Secret Invasion. Although this is more a Changeling Tale for superheroes and villains having Skrull infiltrators as Manchurian Agents, various of them have supressed their memories of being Skrulls and, even more, they do believe were Human All Along until the Arc Words are pronounced and they discovered the truth (for their own horror.)
- In the Mork & Mindy fanfiction Mork and Memories, Mork deliberately makes himself forget he's an alien because due to a misunderstanding, he thinks Mindy wants him to be a human. Eventually, he gets his memory back, resulting in him realizing that he's an alien.
- In Neither a Bird nor a Plane, it's Deku!, Izuku Midoriya is an adopted baby Kal-El, but he's unaware of this until his newly developed Super-Hearing allows him to overhear Dr. Tsubasa telling his parents that his powers could not be the result of a Quirk, metagene, or magic. Inko and Hisashi are forced to break the truth of his origins to him after he wakes up from Sensory Overload.
- Marvel Cinematic Universe
- Seen for the first time in Thor with Loki. All his life he thought he was son of Odin and brother of Thor, but during the movie discovered his real origins: he was a baby Frost Giant (a brutal race enemy of the Asgardians) adopted by Odin. This revelation becomes the Establishing Character Moment for him, making his definitive FaceHeel Turn.
- Played With in Guardians of the Galaxy. Peter Quill's mother is human and all his life thought his father was too. At the end of the movie, he survives handling one of the Infinity Stones (Power) with his bare hands, and a medical analysis afterward reveals it's because he's a Half-Human Hybrid. This launches the story of his next adventure looking for his father, who turns out to be a Celestial.
- In Captain Marvel (2019), Carol initially believes she's a Kree named "Vers", and she doesn't have memories of her past except flashes, which may or may not be real. In the second act, she learns more about herself: she actually had a life on Earth, as a test pilot in the Air Force. This isn't a true inversion of the trope, however, because Carol did receive Kree blood to save her life and so isn't entirely human.
- Escape to Witch Mountain concerns two kids with Psychic Powers on a Quest for Identity. In the end, it turns out they're from another planet.
- In the 1992 movie The Distant Home, 12 year old Sally first discover that there's something wrong with her when she's in an accident and her injuries heals up almost immediately. Then at the hospital, the doctors find out that she has two sets of internal organs; two hearts, four lungs, etc. Turns out she's an alien princess.
- Doctor Who:
- "Human Nature"/"The Family of Blood": The Tenth Doctor turns himself into a human with Fake Memories and works as a teacher in the Edwardian Era to hide from a group of short-lived villains. Naturally, "John Smith" eventually discovers the truth about himself, and he's terrified of it.
- In "Night Terrors", the Eleventh Doctor, Amy, and Rory are trying to help a nervy little boy and solve the mystery of why his fears are coming true. It turns out that the boy's an alien who has Psychic Powers that make all his thoughts (positive, neutral, and negative) to manifest in reality.
- Star Trek: The Next Generation
- Inverted in one episode where boy was adopted by an alien as a toddler and assumes he's the same species, but he's actually a human.
- The episode "True Q". A woman named Amanda Rogers comes aboard the Enterprise as a Starfleet intern to study with Doctor Crusher. During the course of the episode it's revealed that she's actually a Half-Human Hybrid, the product of a human being and a member of the ultra powerful Q Continuum.
- Voyage To The Stars: In "Stewtopia" science officer Elsa Rankfort learns of the existence of a highly-advanced Human Alien species called "rankarts" and latches on to the idea that she is one of them, though it's left uncertain at the end of the episode. In the season 1 finale they get hold of a sample of rankart DNA which suggests she's a rankart/human hybrid.
- ClayFighter: Blob is a clayfighter who can shapeshift in the form he wants, but at the beginning he thought he Was Once a Man mutated by the clay meteor in the circus. But later in his ending in the first game he discovered he was an alien all the time, and even that he came to the Earth along with the clay meteor.
- Phantasmagoria 2: Some ways into the game, Curtis Craig experiences strange phenomena and visions of a humanoid alien called the Hecatomb, while working for the pharmaceutical company Wyn Tech. When Curtis sneaks into its basement level, it turns out that his boss Paul Warner was not only in league with actual aliens from Dimension X that create his drugs from live humans and other materials, but that Curtis is actually a clone made of slime and dead rats that the aliens made when Warner threw his original self into the portal, and that the Hecatomb is a mental projection of the original Curtis, who wants the life his clone lived for him.
- Inverted in Futurama: Leela always thought that she was an alien who had been abandoned by her parents, but eventually discovers that she has always been a human, albeit a mutant. Her parents left her at an orphanage and made her look like an alien because mutants are horribly discriminated against and since she could pass for an alien, they wanted to give her a better life.
- Subverted in The Loud House episode "Not a Loud". Lincoln finds out that his birth story is missing from his baby book, so he and his friend Clyde try to find out why. They ask Lincoln's four eldest sisters what happened and one of them, Luna, remembers seeing a lot of men in black suits and so the boys wonder if Lincoln is an alien and those guys were The Men in Black, especially because Lincoln has white hair. Eventually, it's revealed that Lincoln is actually human. The guys in black suits were just there because he was delivered by the First Lady.
- In the season 3 premiere of She-Ra and the Princesses of Power Adora is revealed to be a First One who was pulled through one of Hordak's portal experiments as a baby.