Who or What Is the Hat Man?

The Hat Man is seen worldwide: a tall shadow in a wide-brimmed hat, appearing in sleep paralysis or in the corner of a dark room. Who or what is he?

The Week: https://theweek.com/97457/who-is-the-hat-man-the-nightmare-shared-by-dreamers-across-the-world
Naming the Fallen Angel Who Terrorizes Me: https://rumble.com/v46thsi-naming-the-fallen-angel-who-terrorizes-me.html
Medium: https://medium.com/p/29b729c2f5cd/
The official Orthoprax Christianity website: http://orthopraxchristianity.org