Shitty Fantasy Idea
A "person falls into fantasy world and are told they're the chosen one" story, but the one telling them they're a hero is this pixie who's just doing it for the shits and giggles and our anti-hero is suuuper suspicious of it, so they keep asking for different clarifications ("So they specifically mentioned my hair color?") until somehow the pixie's race is brought up and the not-hero casually calls them a fairy, not really knowing the difference, and the pixie loses their shit, yelling about the differences and the not-hero responds with "ok, fairy" cause they're a little shit.
Anyway, cue the pixie deciding they're going to make this person think they're the chosen one if it's the last thing they do, and the not-hero using the pixie as a way to figure out where the fuck they are and what they should do so they dont die.
Basically they keeping conning each other until the pixie accidentally trains the person enough that they become The Hero and defeat whatever evil was nearby. Also throw in a good ole enemies to family/lovers while you're at it.
