What causes someone who was good turn into a Monster the next day? Does that mean it can happen to any of us?

The pred was always there

People have this misconception that people turn evil unaware that the evil has always been in them. It's the thoughts and feelings we like to down play and forget and seperate ourselves from but its there

Predation was part of his/her makeup. You just didn't see it.

And no, it's not normal or catchable like a common cold. It means someone is a psychopath. That's typically both DNA and environment as causation.

It could happen to anyone.

It requires lack of self awareness and constant disagreements and disappointments to turn into a Monster but it happens gradually and in layers.
It mostly happens to the loners.

No, it doesn't mean that…there had to be some predatory tendencies in that person's psyche to begin with (and not everyone has those tendencies).

I dont think its ever that simple. It takes more than just a few eggs and an oven to bake a cake.

If they are a preator, then they were not good, they only fooled you into believing that.

They were probably hiding their true nature.

I don't know what causes it. I don't think most people are like that.

Brain Tumor, Bad Drugs, Psycho, Parasitic Alien Control

Must be some kinda virus?