dizzy All of those have been debunked. The top two were debunked years ago and I'm pretty sure the bottom was one of many ai slop img's made to trick people hunting for the img.
Cicada 3301 is a classic internet mystery, but thats kinda well known.
A more obscure one I know was the Cannibal Café Forum that got shut down because a member actually ate another member.
There was a tumblr/facebook witch that gave away human remains but idk how much of a rabbit hole that counts as
