"They are strange, invisible creatures of the dark. They could steal upon you at night, smother you in a dark mist and take from you the will to live. They can creep through open windows and come into houses to cover an unsuspecting sleeping victim like a dark blanket. Once the victim is seized, he couldn't move. They would take his strength and fill his mind with horrifying, hideous thoughts. They would leave their victims listless and heavy-limbed, with sunken eyes from the sleepless nights spent fearing their return."