Hat man phenomenon. It's a very common sleep deprivation/sleep paralysis hallucination. It's actually pretty interesting, since it's only been common for a few decades, likely due to movies involving tall scary men with hats.
Madness string 111266
By the way, I'll tell you that in Belgian Congo there's not a single person who tells the truth. They just lie all day long. Start at seven in the morning and keep at it until nightfall. So if I lie a little now and then, it's just because I've spent a little too much time in Belgian Congo.