Bloody Mary

From Omnictionary

Bloody Mary is a well known urban legend, of an evil old hag who will be summoned, and subsiquently kill the summoner horribly, by saying her name three times in a mirror. There are many varient to this, but that is the most well known part of the legend. The identity the specter is uncertain, but many folkloreists have claimed that legend was started in England after the death of Queen Mary, who was also refered to as Bloody Mary during her life.