As the legend goes, the evil spirit Bloody Mary can be summoned by chanting "Bloody Mary" anywhere from three to 1,000 times into a mirror in a darkened room lit only by a candle.
After the right number of chants, the spirit will appear in the mirror either as a corpse, witch, or ghost, sometimes covered in blood, then she'll lean forward and claw your eyes out, or pull you toward her, trapping you with her in the mirror for eternity.
Fact: Bloody Mary herself may have been real. Some people believe she was a witch that dabbled in the black arts, while others claim she was a regular woman involved in a fatal car accident. Then there are those who believe she's Mary Worth of Salem Witch Trials fame, or Queen Mary I of England. No matter what, it's probably best to avoid saying her name into a mirror.