The "Bloody Mary" face in the mirror legend is an urban myth in which young people, usually girls, look into a mirror and repeat a chant to summon a demon, ghost or witch. The image that appears in the mirror may be perceived as either friendly or evil.
The urban legend, which has numerous variations, is often considered a rite of passage for young women. The ritual and chanting often occurs at slumber parties. Instead of just saying "Bloody Mary," sometimes the names "Hell Mary," "Mary Worth," "Mary Whales," "Agnes" or "Black Agnes" are used.
Variations of the chant include, "I believe in Mary Worth," "Bloody Mary" and "I stole/killed your baby Bloody Mary." According to the urban legend, the apparition is sometimes headless, or only blood appears.
The game first appeared as a way for young women to see the images of their future husbands. Participants needed to walk up and down a flight of stairs backwards while holding a mirror in one hand and a candle in the other. Staring into a mirror for a prolonged period of time can induce hallucinations. Other forms of hallucinations such as self-hypnosis are also used to explain people's reactions to the activity.
The Bloody Mary legend continues to be one of the most popular slumber party games throughout Western society as of 2015.