This was suggested by EPICNESSQUEEN21

Freddy: You've always been afraid of Freddy. He's been haunting you for years after all

Jason: You were always wary and scared of Jason, you knew what he was capable of doing

Michael: Once you walked in on Michael carving out someone's throat... We'll leave it at that...

Leatherface: Despite Thomas being kawaii as hell, he was terrifying when he wanted to be. If anyone threatened you then he became vicious and sawed them in half. And you watched it happen...

Hannibal: You've been afraid of Hannibal since you found out he was a cannibal

Norman: One day a man had come to the motel and kept making passes at you. Norman had had enough and went up to the man and stabbed him repeatedly then sliced his head off using a kitchen knife. You were afraid to be near Norman after that

Ghostface: Ghostface is just scary to you from everything he's done to you

Jack: You were there when Jack went homicidal and tried to kill his family, that scared the shit out of you. So you tried to stay on his good side

Pennywise: Pennywise's existence has scared you ever since you were a kid

Will: Once a man had broke into your house and Will went to go take care of it. Instead you watched as Will mauled the guy. He used his claws and fangs to rip out the man's organs and gouge out his eyes. You spent some quality time with the toilet after that, throwing up and trying to get that mental image out of your mind