They came only at night. They crept around the dark places, the hidden places, the poor and lonely places. It was said in the city that you could tell when they approached. First your skin began to prickle and then a sickening cold fear lodged itself in your belly which rose and rose, up and up - until you could not speak and you could not breathe, and the lamp that you were carrying couldn't bear it any longer and went out - phoomph!