Not exactly creepypasta, but I do believe the SCP Foundation would make a cultural splash if it were invented today: https://scp-wiki.wikidot.com/scp-series
It might be my bubble, but it feels like SCPs are quite known in the internet culture. I've seen surprisingly many references on HN alone, for example.
Hah! My 10 year old knows every single one of those things, their rating, and the complete history of the scp foundation. It’s a pretty complex story.