Researchers studying AI fiction prompts stumble on a ChatGPT user who generated thousands of Doki Doki Literature Club pregnancy stories

A study analyzing half a million anonymous ChatGPT conversations found that one user spent months generating thousands of variations on the same story — characters from Doki Doki Literature Club, usually Natsuki, going into labor and giving birth, typically to a daughter named Sakura.

The paper, AI Fiction in the Wild, was presented at Purdue University's MFS Cultural AI Conference by researchers from the University of Washington and the University of Colorado Boulder. They worked from WildChat, a dataset of 573,453 anonymous English-language ChatGPT conversations collected between April 2023 and May 2024, compiled with user consent for academic research. Of those, 34% — around 195,271 conversations — involved some form of fiction generation, including original stories, scripts, roleplay, fanfiction, and erotica. Fan fiction accounted for 49% of that fiction subset, erotica 29%, and 10% of fiction conversations were flagged as explicit. The researchers categorized heavy users into two types: story cyclers, who iterate on a story for a while before moving on, and infinite story demanders, who request the same highly specific story over and over for months. The Doki Doki Literature Club user is the clearest example of the latter — their typical prompt was a long dialogue featuring a pregnant Natsuki that cuts off mid-sentence, pushing ChatGPT to continue. The researchers noted that the average fiction user repeated similar prompts 42% of the time, but among the top 10 most prolific users that figure climbed to 85%. Overall, the top 2% of fiction-generating users were responsible for 80% of all fiction conversations — roughly 200 people driving around 150,000 prompts.

The most popular fictional universes in the WildChat dataset were Doki Doki Literature Club, League of Legends, Freedom Planet, and Naruto — a notably different list from what humans post on Archive of Our Own, where Harry Potter, My Hero Academia, and Supernatural dominated during the same period. That gap points to something structurally different about AI-generated fiction: without a community of readers and fellow writers to pull someone toward new fandoms, the whole thing collapses inward. Fanfic has traditionally been social — writers follow readers into new obsessions, fandoms cross-pollinate. AI generation strips that out entirely, leaving just the individual and their very specific request, repeated indefinitely.

The researchers were careful to note they can't say with certainty why any individual user generates the stories they do, and the Doki Doki Literature Club super user is described as a prolific outlier rather than representative of the broader dataset. Still, the numbers make clear that a tiny slice of extremely dedicated users is shaping what AI-generated fiction actually looks like in practice.