The closest any singular video game has ever come to being designated as an SCP
It's like Street Fighter/King of Fighters/Super Smash Bros, if its character roster was built out of the Akashic records and took the form of an impossible shape optical illusion

I don't know how the community is now, but back in the 2000s/early 2010s it was a bureaucratic nightmare hellscape ruled by Napoleons, the worst possible community for a game reliant on user-generated content, with so many rules, moral prohibitions, and warring factions (warehousers vs. creators) that it'd make Kafka shit his pants and die
This game is basically the video game equivalent of the King in Yellow, an impossible forbidden game that drives its players to madness, when I was a 12-year-old autistic child with strong convictions about preservation, my actions in the community made people threaten to kill me and dox me and send fake reports to the FBI over me (which is a felony btw! epic win) which definitely has NOT fucked me up for life with anxiety issues

There used to be a list of "unrequestable characters" that were prohibited from distribution due to stolen code, or stolen art, or because they just didn't like who made them, and that instantly turned every character on that list into a hot commodity all of us WAREHOUSERS just had to find

We were all assholes and deserved each other, like we had all sinned during a previous life and this community was our punishment

P.S.: a "warehouser" is defined as somebody who engages in unauthorized distribution of MUGEN content, you would become a social pariah if you shared characters without permission, even if those characters had been offline for years and would be lost permanently without reuploading, you are still catching a ban