The scariest-looking baseball player ever

I've heard a lot of talk. And Dave Stewart's name has been mentioned quite often. But no one has come up with a definitive answer.

I think we need to have an answer.

Who was/is the absolute scariest-looking player in baseball?

Comments welcome. Supporting arguments recommended.

A long post containing nonsensical yet vaguely-entertaining conjecture and speculation will follow at a time of my choosing.

Good day.