When does a man become a monster?

I was told to look out for the men that prowled through the streets at night, snatching young children from their beds. I was told they would be disfigured, easily distinguishable from you and I. They would growl and snarl and hiss, too inhumane to communicate.

Lately I have been feeling something wrong, something Other, inside of me. I am still me, I walk and talk the same, say hello to my neighbours and make polite small talk with the cashier at the grocery store. But something isn't right and I fear I am to lose myself if nothing is done. Is this how it begins? Was every man an average Joe like you or I, before something took hold deep within?

So I ask you, When does a man become a monster?