Born as an Adult

When a creature or species essentially comes into the world in an adult body. This may result from the creature having been deliberately created by someone else, or it just may be the way their species works.

If the character is lucky, he, she, or it will be born with the skills to survive in the world. If not, the character is probably in for a very rough and awkward time.

Such a character is potentially subject to Merlin Sickness—being born old but then proceeding to age backwards. It's also possible that the character Really Was Born Yesterday.

Examples of Born as an Adult include:

Anime and Manga

In Dragon Ball, King Piccolo's children as soon as they hatched they were fully grown and ready for battle, Piccolo Jr. was the only one who was a baby when he hatched.
In a scene from Gall Force, this is suggested to be the case with the Solnoid species.

Comics

DC Comics: Kon-el/Superboy was cloned and 'born' as a teenager with some knowledge implanted inside his head. Apparently the same went for his clone, Match.

Film

Judge Dredd. The clones Rico created in the lab would have been full grown if they had lived.
In the film Repli-Kate, the hero scientist unintentionally creates a clone of Kate, a Hot Scoop who was doing a story on his research. The clone, which they name Repli-Kate, is physically an adult but doesn't know anything, so the hero and his friend educate her, and thanks to her fully developed brain, they manage to teach her language and how to behave like an adult inside of a few days.
Rocky Horror Picture Show: Rocky.
The egg-born Uruk-hai in the film of The Lord of the Rings.
The entire point to watching The Curious Case of Benjamin Button.
Samourais- a Japanese woman is pregnant with a demonic entity, and she, as well as the main characters, is trying to stop it from being born. They fail. She gives birth to a cocoon-like sac, which a fully grown man rips out of.
In the horror movie Embryo, Rock Hudson is a scientist who develops a way of fast-aging fetuses in incubators, so they're adults by the time they become conscious. Said fetuses (fetii?) also have super learning skills, allowing them to become an Instant Expert in anything they study. Unfortunately the development process has some unfortunate side effects...

Literature

In Wicked, Yackle turns out to have been born well past full-grown from the Grimmerie.
Disney Fairies: Fairies come into being appearing to be young adults.
The cloned super-soldiers of the Ghost Brigades in the Old Man's War series.
The golems in the Discworld novels are created (forged) in adult form. And they stay that way for a long, very long time.
Frankenstein's Monster.
The Curious Case of Benjamin Button.
The protagonist of "Second Person, Present Tense" by Daryl Gregory. More or less.
In The Kalevala, where Vainamoinen is born at the age of 700. The pregnancy took that long too.
There's a side story to the Tortall Universe in which a tree is accidentally "born" as an adult man (a sorcerer unwittingly did this when he transformed an enemy into a tree). While the tree-turned-human is magically given knowledge of the human world by the sorcerer to help him get along in the world, he himself has virtually no firsthand experience and finds himself depending on a "young man" he meets.
One of the Doctor Who Virgin New Adventures novels claimed that Time Lords have lost their ability to reproduce naturally, so new Time Lords are made by genetic engineering and emerge fully-grown. This doesn't seem to have held in the TV series.

Live Action Television

In the Star Trek: The Original Series episode, "The Trouble With Tribbles", Dr. McCoy states that tribbles are "born pregnant", which implies an adult reproductive system.
- There's a type of Real Life mite that has a reproductive cycle exactly like this. Every female is born pregnant; males aren't born at all, because they impregnated their sisters before any of them were born, and once he's mated his usefulness is over, so he just kind of dies inside his mother. Aphids are also born pregnant, but such offspring are clones of their mothers.
- In the original series episode, "I, Mudd", the androids are apparently "born" as fully functional adults.
- In Star Trek: The Next Generation, Mr. Data's "species", the "Soongian androids", are apparently born with adult bodies, but rather robotic personalities. As their positronic neuroprocessors age, they develop childlike personalities before becoming fully adult.
Kyle in Kyle XY (also, Jessi too).
In Angel, Jasmine is born as a full-grown woman. She's of the "born with world survival skills" variety (or in this case, world-destroyer skills).
Lexx season 3 might count: nobody on the planets Fire or Water recalls being a child; they just woke up one day and there they were. (This might be explained by the implication that the two planets are actually Hell and Heaven).
Doctor Who: The cloned soldiers in the episode "The Doctor's Daughter" begin life with an adult body and full military training.
Alternately, this trope could also apply to beings that are born normally but age near-instantly to adult status, like Jeff Bridges in Starman or Liam Kincaid from Earth Final Conflict.
Bender (and probably all the other robots) in Futurama.
- The series kind of ping-pongs on this; sometimes it depicts him as being "born" as an adult, but having a baby-like mentality until he received his bending programming, while other times it depicts him as an actual baby robot, of baby scale (once it showed his "fetal" form as a disc containing bending unit software).
One Saturday Night Live skit had this happen to Will Ferrell.
On Mork and Mindy, Orkans age backwards, thus they are born as adults and become children as they get older. In the final season, Mork and Mindy had a son who hatched from an egg as a full grown man (played by Jonathan Winters).

Mythology

The Bible: Adam and Eve.
Greek Mythology
- The goddess Athena was "born" out of her father Zeus' head fully grown and armored! (some versions state that she was actually born and nurtured by her mother in Zeus' stomach (Zeus had swallowed Metis to keep her from having children who would overthrow him) and only emerged late once fully grown)
- Aphrodite is another Greek goddess who was born an adult: she was created when Cronus severed Uranus's genitals and threw them into the sea, and Aphrodite sprouted full-formed from the sea foam.
Monkey of Journey to the West was born full-grown from a stone egg cut out of a mountain. Not much explanation is given for this.
Norse Mythology
- Váli was said to been born as an adult, with the goal of avenging Baldr.

Tabletop RPG

Gamma World adventure GW1 The Legion of Gold. The cyborgs in the SAMURAI underwater laboratory are created full-grown and then have their brains programmed.
Dungeons & Dragons.
- If the Clone and Stasis Clone spells were used on adults, the clones they created would be adults too.
- In the Forgotten Realms setting, Living Constructs (Alias and her "sisters") were based on one of their creators' modified clone and thus created in adult form. The first has escaped after receiving Fake Memories, but the second generation was released as is and thought they had an incurable amnesia. Their built-in protection from divination magic prevented anyone from discovering the truth.
Promethean: The Created: The vast majority of Prometheans come into the world as adults. In fact, it's a necessity for the creation process that the body used has to have undergone puberty. Mind you, when they're born, all they have is a rudimentary understanding of the old body's main language and a set of autonomic functions.
Paranoia sometimes has clone bodies quick-grown to an adult state.

Video Games

Guild Wars 2 will do this with Sylvari.
Grunt in Mass Effect 2, grown in a lab tank and educated through neural downloading
Klaymen himself in The Neverhood was created in his current form.
The Murakumo units including Noel Vermillion of BlazBlue.
In Tales of the Abyss replicas are identical to their originals as they were at the moment of creation. However, their minds are complete blank slates, save for a limited capacity to be programmed with basic commands.

Web Comics

Everyone in Erfworld 'pops' full-grown - one of the first things to really bend Parson Gotti's mind - he asks a sorceress what she was like as a child, and gets a blank look. (This fact, by extension, also means that Erfworld has a much more casual attitude towards sexuality than a medieval society normally would, as well as general equality of the sexes since women aren't held back by pregnancy.) Regardless, this is of the 'it's just how it works' variety - presumably because their entire world is designed around warfare, so there's no room for kids (or civilians, for that matter).

Web Original

Fenspace: Most (but not all) of the AIs "wake up" ready to take their places in society.

Western Animation

Thumbelina: When she is born she is at least a teenager.
Smurfette of The Smurfs, created by Gargamel and changed into a real Smurf by Papa Smurf as an adult female Smurf.
Double Subverted in Gargoyles by Thailog. When first created, he was just a hatchling. However, he was placed in a nutrient bath which sped up his aging for as long as he stayed in it.
In Monster High, this is suggested to be the case with Frankie Stein, who starts attending high school at the tender age of 15. Days old, that is.
Superboy in Young Justice looks to be in his late teens, but he was essentially 'born' in the first episode. In his case, because he's a clone of Superman, grown in a pod.
Across various series, Transformers are almost always shown to be "born" in adult bodies. Of course, that's probably a result of them being Mechanical Lifeforms.

Real Life

There is at least one species of frog that remains in their egg for the entire tadpole period and only emerge once they reach adulthood.