[bitwize]

I don't think believability as in fooling you into thinking the events were real are as important as verisimilitude, the feeling that it could happen.

An example: In the late 90s, back in the days of pervasive browser pop-ups, there was a Japanese creepypasta-equivalent called "The Red Room", about a browser pop-up that read "Do you like the red room?" Ignoring or closing the pop-up was said to seal your doom. The most popular form of this story took the form of a Flash animation which depicted a boy who saw the popup appear on his computer.

As a finale, after showing the boy meeting his grisly fate, the Flash site caused the popup to appear on your computer.

Not really believable when you think about it. But scary, because it gets you into a headspace of the fictional universe and then breaks the fourth wall, giving you a fleeting feeling that the Red Room curse is real.

I think if creepypasta didn't exist we would have to invent it. It's part of a horror tradition that encompasses Poe and Lovecraft, and even before. Creepypasta comes from the same place as primordial ghost stories told around a campfire, just with updated media and sensibilities.

[permo-w]

"red room" seems to be a recurring term in creepy stories. I can only specifically recall this and those dark-web stories you hear on clickbait youtube channels, but I feel I've heard it in other creepy/negatively-emoted settings too

[bitwize]

H.G. Wells wrote of a red room as well in a "creepypasta" of his own: https://en.m.wikipedia.org/wiki/The_Red_Room_(short_story)