Usually, a sequel shows what happened next in the world of the original work. This trope is when a sequel or spin-off shows what happened next in a world where the original work is only fiction.
A common aspect is that although the sequel (or spin-off) is generally constrained to be the same genre as the original (otherwise, why make it a sequel?), setting it in a different world allows the creators to go as Broad Strokes as they like, and play with things not working according to the rules viewers would expect from the original.
May include an invocation of The Fourth Wall Will Not Protect You, especially if it's in the horror genre.
Compare Nested Story Reveal, where part of a story is revealed within the same work to be fictional; Recursive Canon, where an earlier work in the series is real but also has an in-universe fictional work based on it; and Legend Fades to Myth, where an earlier work in the series is real but has become a legend in the time of the current work.
Unmarked spoilers ahead!
- Digimon Tamers: The TV and game franchise Digimon is only a work of fiction. Then real Digimon start showing up. The tone is generally darker than most Digimon stories, with elements of deconstruction.
- The Gundam Build branch of the Gundam franchise contains stories in which the rest of the franchise is fiction, but new technology has allowed fans to create working replicas of the Gundams and pit them against each other in non-lethal combat. The tone is generally lighter than most Gundam stories, with elements of self-parody.
- "Princess Celestia Hates Tea" involves Celestia admitting that she dislikes tea, and all Hell breaking loose as a result. The sequel, "A Short Story by Twilight Sparkle", reveals that all of those events were just a story that Twilight wrote—and the real Celestia wonders why Twilight caricatured herself so viciously in that story.
- The Flash (1950s reboot): Flash Comics is only a work of fiction, and the Flash is "just a character some writer dreamed up". A fan of the comic book gains similar powers in a Freak Lab Accident, and decides to base his superhero identity on the comic book character. The choice to turn this version of the comic into a Continuity Reboot, rather than a simple revival, and make the older comic fictional in-universe, was the first step towards establishing the DC comics continuity as a multiverse, with far-reaching results to this day.
- Solar: Man of the Atom (Valiant Comics reboot): The comic book Doctor Solar is only a work of fiction. Phil Seleski, a fan of the comic book, gains energy-based super powers and splits into two beings, one of whom is based on Doctor Solar.
- Bewitched (2005 film): The TV series Bewitched is only a work of fiction. The part of Samantha in a remake goes to a real witch-passing-as-normal; Hilarity Ensues.
- Book of Shadows: Blair Witch 2: The movie The Blair Witch Project is only a work of fiction. A group of fans go to visit the locations where the movie was shot, and have a horrifying possibly-supernatural experience.
- Both the second and third The Human Centipede films: In The Human Centipede II, the original is only a movie. An obsessed fan of the movie decides to make his own human centipede. The third film, The Human Centipede: Final Sequence, similarly has the first two films as fictional and inspiring its villain.
- Wes Craven's New Nightmare: The movie A Nightmare on Elm Street is only a work of fiction. The actress who played the Final Girl starts experiencing supernatural phenomena similar to those her character had to deal with.
- Danganronpa V3: Killing Harmony: It is revealed toward the end that all the preceding Danganronpa stories are fictional in-universe, and quite popular. When world peace proved far too boring for humanity to handle, it was decided that the franchise be adapted into a real-life reality show where teenagers willingly sign up to become brainwashed with the identities of Danganronpa characters and kill each other on live TV to sate humanity's bloodlust.
- In Soushuu Senshinkan Gakuen Hachimyoujin, the Shinza Bansho Series by the same author is apparently a popular fighting game series of which Ayumi is a huge fan of, owning at least one of the titles and seemingly likes to sing Einsatz when she gets the chance.