[Elsa looks at her hands in surprise and wonder]
The Professor has some really cool experiment going on. Probably involving biology, computers, or something like that. The result is indeed cool. In fact, it's so cool that it has the unforeseen side-effect of being an actual person. Whoops!
This new person or species is benevolent, and quite obviously worthy of human rights. Obvious to the audience, that is. The creators might fail to understand this, thus causing all kinds of trouble. However, in some cases, rejection from the creators may lead the created character to resentment or worse.
Supertrope of Instant A.I.: Just Add Water! and It Came from the Fridge: If the unforeseen intelligence is technological or culinary in nature, see that trope instead. Examples of ambiguous nature goes on both pages.
- In the Lucifer chapter The Yahweh Dance, Elaine creates a new universe as a part of training to be a good God. While a carefully monitored intelligent species arises, these events distract this new and inexperienced God to overlook another continent, and the sentient species evolving there. The rest of the plot is spent by God trying to stop the chosen people from slaughtering this other people in God's name.
- In Journey into Mystery young Loki, in an effort to humanize the Serpent, an unbeatable enemy, added a romantic sub-plot to his biography. Said sub-plot, who was modelled after his best friend Leah, later appeared basically to go Rage Against the Heavens / Rage Against the Author on his ass. At the end it was revealed that she grew up to become the goddess Hela.
- In issue #7 of the Invader Zim continuation comics, Zim crash lands on a lifeless Death World. Fuel leaking from his ship then somehow reacts with the planet to create a primal ooze, from which emerges a rapidly evolving ecosystem, including giant carnivorous ladybugs and sentient amoebas that worship Zim. When Zim ultimately leaves the planet, he blows it up... at the amoebas' insistence, as they think it's the only way to please him.
- In one Sherman's Lagoon arc, Megan tries her hand at the world's most complicated recipe, the final step is that it needs to be struck by lightning to be cooked. Once it cools down, the casserole gains a life of its own and starts walking around like a humanoid blob monster! However, what bothers Sherman isn't the implications of creating life from a collection of foodstuffs, it's the fact that he no longer has dinner.
- In the shared backstory for Queen of All Oni and Queen of Shadows, Kagehime created the first Shadowkhan from her shadow accidentally, as she'd never seen a shadow before (having been born and raised in the lightless depths of The Underworld) and mistaking it for a person, which willed it to life.
- In Disney's The Black Cauldron fanfiction Hope for the Heartless, Creeper is revealed to have come into existence by accident. The Horned King was preparing a concoction for an unstated purpose when a little statue fell off the decaying castle that served as the work area and Creeper was born. That experiment had taken centuries to get to that point, and the Horned King despises Creeper so much for ruining it like that.
- In Stygian Solace, Yami is revealed to be have been a total accident. He was created when Ansem body-jacks Kairi due the inability of Riku. Kairi's pure heart purifies Ansem to create someone else entirely.
- In Ages of Shadow, Jade/Yade Khan's power reacting with the energies released in the Final Battle seeds the Shadow Netherworld with simple life, as well as creating four infants.
- In The Parselmouth of Gryffindor, walking catastrophe of a wizard Professor Lockhart tried to "de-spell" a perfectly ordinary statue, believing it to be a disguised monster. Somehow, his backfiring spell ended up actually giving life to the statue instead.
- In addition to being able to create ice and snow, Queen Elsa from Frozen can create sentient life in the form of snow people. This happen when she conjures up hers and Anna's childhood snowman Olaf during "Let It Go", completely unaware that her abilities mean she's given him life, which Anna and Kristoff end up finding out first. Subsequently, when Anna does arrive at Elsa's ice castle and Olaf inadvertently barges in prematurely (after giving Anna a minute), Elsa is surprised to find that she even brought Olaf to life. Her creation of Marshmallow on the other hand is not at all accidental, and much less benign.
- In TRON: Legacy, Flynn creates life on purpose, and all is well. Then a whole new species emerges from the grid's complexity without any conscious input, and he thinks that's even cooler. And then one of his original creations, acting on the flawed remit to "create the perfect system", comes to see these new beings as "imperfect"...
- Heck, the whole franchise has a lot of this going on. The closest we get to an explanation as to what the Programs are is the scene where Encom's founder Walter Gibbs rants at Dillinger that "Our spirit remains in every program we design!" The old man didn't mean it literally; the Encom programmers had no bloody idea that they were coding up sentient beings.
- Weebo the flying computer from Flubber was a "glorious accident," and can't be repaired when she is damaged. However, she designed an improved version of herself that shows up at the end. The Flubber itself is far more alive and intelligent than intended.
- In The Rocky Horror Picture Show, Frank claims that it was an accident that made everything fall into place when he was trying to create Rocky.
- In the Cthulhu Mythos, Azathoth created reality itself by accident.
- Also in the Cthulhu Mythos, it is suggested that all organic life on Earth is an unintended offshoot of the Elder Things' decision to cook up some shoggoths.
- Sort of the whole point of The Dollmaker.
- David Eddings' Sparhawk universe (the Elenium and Tamuli trilogies) features the Child Goddess Aphrael, who willed herself into existence, although it's not made clear whether this was a deliberate act. Given how whimsical she can be, it's not impossible that she did it inadvertently.
- Discworld: According to one dwarf creation myth, Tak (the Dwarf's creator-deity) created man and dwarf on purpose, then saw the rock he'd made them from was trying to come to life. Impressed by this, he turns it into the first troll. The alternative, favored by particularly racist dwarves, is that he never noticed and so trolls aren't really alive.
- Kamen Rider Ex-Aid: The Bugster Virus, and by extension Bugsters, came into existence because of a hitch in computer code. They are sentient beings, even if bound by the programming of video game characters. Deciding what to do now that the life has been created and threatens the pre-existing life is important part of the story.
- The entire point behind the BIONICLE story was that Mata Nui, AKA a planet-sized space-robot whose body houses the Matoran Universe, was meant to function as a sentient but lifeless robot, along with everyone living inside him. Instead, they built up cultures, began worshiping Mata Nui as a deity, developed relationships, formed alliances, fought wars... Sadly, this didn't cause another creation of the Great Beings, Marendar, from seeing them as more than just robots, and began to carry out his task of shutting them off. Well, "slaughtering" would be a more fitting expression.
- In Scarred Lands, the Titan Thulkas often created entire species, sometimes sentient ones, without even noticing. Goblins and giants are among his creations. It is implied that the humans are as well, since they were created before the Gods (thus by the Titans) but nobody knows for sure which Titan it was, and none of them claim credit for the deed.
- Dungeons & Dragons' Eberron Campaign Setting has the Warforged, android-like machines that were built as mindless soldiers but spontaneously developed sapience and became "living constructs", which even gives their mechanical bodies a form of life. Their creators, the artificer House Cannith, were a bit dismayed that their creations developed free will and gained citizens' rights.
- In Magical Girl Lyrical Nanoha A's Portable : The Gears of Destiny, Amita and Kyrie were revealed to have been created as Ridiculously Human Robots by accident. Their creator was just planning to create non-sentient automatons, but he kinda overdid their programming. Once he realized what had happened, he adopted them as his daughters instead. He toned down the programming for later batches, since he still needed non-sentient robots to work on the restoration of Eltria's deadlier regions.
- Jyrras of Dan and Mab's Furry Adventures created two different lifeforms, both by accident, in the form of Deebs (a childlike bunny-girl of living, floating pink bubblegum) and a Robot Girl.
- Molly the Monster from The Inexplicable Adventures of Bob! was born accidentally from a test tube full of... something getting spilled into a jar of crunchy peanut butter.
- In El Goonish Shive, Arthur intended to create a talking wand for training wizards. It didn't work at the time, but when the properties of magic slightly shifted, it suddenly started working. Thing is, it was originally supposed to simply verbalize lessons, but it instead became a Snarky Inanimate Object that calls itself "Kevin". Arthur takes it reasonably well, saying that "as my daughter would assure you, I support life I have unintentionally created", and since Kevin has decided he wants to train Ashley, Arthur allows it.
- The Simpsons: In a pastiche of an episode of The Twilight Zone (1959), there was a Halloween Special where Lisa manages to accidentally create a tiny living civilization in a "tooth in cola" experiment, along with a convenient spark of static electricity.
- Ben 10: Omniverse reveals in a flashback that Galvan-B, Galvan Prime's Moon, was once an uninhabitable dry rock before Azmuth performed a successful Terraform experiment, rendering the Moon suitable for life. It worked beyond expectations, as a new alien species, the Galvanic Mechamorphs, rose on the Moon's surface.
- Played for Laughs on Spliced in the episode "Bowled Over". Peri makes a sandwich, which then randomly grows insect-like legs and wings and begins attacking people. Later, he attempts to fix Patricia's car, but he ends up giving it sentience instead. Also in the episode "Living Hellp", Entree attempts to microwave a microwave, which results in the microwave coming to life and attacking him.
- Ogrest from Wakfu was created during the alchemist Otomai's attempt to forge a new Ogrine heart for the Sadida doll Dathura. Otomai's assistants accidentally tipped over a jar of candy, and one of the treats fell into the forge. The result was a small large-eared baby with tusks. Otomai quickly took a liking to the infant whom he named Ogrest and adopted him as his son.
- The obscure late 80s cartoon show Little Wizards has three of the four protagonists being this; as the Expository Theme Tune explains/shows, Prince Dexter accidentally knocked over a bunch of magical potions and reagents into a cauldron already filled with a magical brew whilst overburdened with assorted magical grimoires and wands. The result was a huge explosion and the creation of his allies and fellow students; the magical monsters Winkle, Gump and Boo.