@kasdeya that's part of it. Yeah. Artists can make fanfiction of characters that typically don't have any appeal to bring appeal to their audience.
Sometimes those characters do have a different kind of appeal. Maybe these characters tap into your sense of nostalgia. Maybe these characters are an icon, a symbol for something?
Of all the characters to make gay, trans, and communist - why did I make it the cast from Nintendo and not Sesame Street?
You ever notice the first thing folks did when Winnie the Pooh entered Public Domain, they turned the character into a horror slasher film? Winnie the Pooh the Original Character represented something to the public and their own childhoods. Innocent, friendly, kind. The directors of the Winnie the Pooh slasher put a mirror to the characters iconography as a means of shock value. And there's an appeal to the public with playing with the iconography of certain characters with what these characters represent.
Why is Thomas the Tank Engine turned into a figurehead for dank weed and Eldritch horror?
Why are the characters from TF2 and Left for Dead going on an endless list of absurd machinima and music videos?
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TLDR:
Not only is it about turning off that critical thinking about why these characters are in these fictional scenarios in order to add appeal to an otherwise unappealing character, it's also about playing with symbolism and subtext that is embedded in the characters themselves. The Fan Fiction brings a distorted lens through these characters and with it creates novel experiences that the public is able to connect with