WORST FANFIC EVER
There are long, drawn-out torture and/or rape fics.
There is Hogwarts Exposed, a series of softcore paedo erotica masquerading as a nudist author tract masquerading as a Harry Potter Next Generation fic, that is also extremely sexist to boot. There is Celebrian. And, while it does not feature graphic sex (but almost certainly only because the inevitable fic abandonment happened just before that, and it definitively has plenty of off-screen sexual horror, graphic violence and fates worth than death… much of it delivered by the “heroes”), Partially Kissed Hero deserves a mention - the best way to summarise it is “tinfoil incel munchkin turns Harry Potter into his DMPC for over one hundred long, rambling chapter”, or alternatively “Harry Potter and the Dunning-Kruger Effect”, and it is still far worse than it sounds.
Disturbing contentThere is a fanfic where the girl from Jurassic Park is eaten by a pack of Compsognatus with vorarephilic descriptions of them eating her genitals. There is a fanfic where Tonks becomes Harry Potter’s slave without any possibility of resisting his commands after the death of Sirius, which he uses to rape her and force her to take the form of Bellatrix LeStrange so he can torture her in the real one’s stead. There is one about a real sports rider having sex with her horse (I presume that the author is not aware that uncastrated stallions are not suitable for riding).
By the way, I have read at least parts of all these fics except the horse fic through PPC or Das Sporking - notably, I have read virtually all of PKH as it was being sporked over the course of more than two years, but of the Tonks the slave fic, that was only the second of many chapters and I could not stomach it, so I don’t know how much worse that one gets -, so I can confirm they indeed exist. Morbid curiosity can be a curse sometimes.
My point is: I seriously doubt that “a good story along but spoilt for GAY S***” would be anywhere close to the WORST FANFIC EVER.
By the way, my knowledge of the franchise comes from Pop Culture Osmosis only, but isn’t “Aang is reincarnated as a lesbian” canon? So it’s not even the fic’s author who would be to blame.