The reason Michael Myers is so scary is because he can tap into our fear of the unknown. There's a very uncanny valley quality about him. He's in the shape of a man, but we can tell that something is off about him.

People are afraid of Michael Myers, the fictional character from the "Halloween" film series, for several reasons. One of the main reasons is his relentless and unstoppable nature. He is portrayed as a seemingly indestructible force, which creates a sense of helplessness and inevitability for his victims.