>>49626598Lavender Town is debatably a proof-of-concept for such a thing. If you wanna go further, there's debatable success in the world of Pokemon creepypasta, though that leans into other things that you might disqualify from it, or it might also be cringey and poorly made. Personally, I do think Buried Alive and White Hand were some of the better ones.
I think the biggest problem is that here on /vp/ if you attempted to try something like that, it would get shitposted endlessly as grimdark edgelord bullshit, regardless of the execution.
Wasn't there also a glitch romhack someone made with new pokemon designs to look terrifying?