So the man who appears in everyone's dreams is apparently not only not a real thing, but was actually part of a marketing campaign for a movie that was canceled. It was supposed to be a horror involving said dude, though I don't know much else about it.
It's sort of like the 'we all eat, on average, five spiders a night in our sleep' myth, which is also not true, but is so passed around that everyone just assumes it must be true - interesting thing about that (spider) myth is that it was actually an experiment to prove that such fake information can become 'fact', and the fact that it's stuck around just shows how good of a job they'd done.