A mod about two narrators, one looks like Curly Brace and one looks like human Sue, who take turns making up a story. You play the story they make up, and in between levels you see their conversations. Not-Curly is the xd memester, and Not-Sue is the dark snarker.
The two go back and forth and change the story once you get through a section (ex. getting the Not-Sue-influenced Bloodstained Locket before going back into Mimiga Village, which Not-Curly turns into BonziWorld). It starts out as a CSBD, but by Egg Corridor the level design is completely original. As the mod goes on, Not-Curly becomes less xd and more sinister and you learn more about the narrators' real lives, and the story they create becomes more symbolic in nature.
After 1 or 2 hours of this, you find out that Not-Curly is a personification of Not-Sue's fears and insecurities, and Not-Sue has been alone in her house for years, talking to her imaginary "friend." The final level ends with you a hopeless boss fight against a symbolic version of Not-Sue's hatred of herself and the world, and the mod ends with Not-Sue strangling Not-Curly before watching as the entire world crumbles around her.
it would have a bunch of anime references and the entire ending would be a shout out to evangelion because im a filthy weaboo
I only got the first room done, then realized I was not willing to put in nearly as much effort as was required.
On another note, I would love to see someone put at least one of the ideas in this thread (not counting ones that are already released mods) into a mod and actually make it good.
EDIT 2020:
Goddamn I was edgy