Many years ago on a Halloween night the doorbell rang and another trick or treater was at my door. I went and opened it expecting to find a couple of youngsters in costumes yelling 'trick or treat' but instead this time there was one lone person on the front veranda.This particular costume was a bit odd. It was all black, a black gown, a black hood, and also a black cloth mask so that no trace of the face could be seen.