The Bloody Mary legend and its several variants date from the 1960s. Like so many folk rituals and traditional tales, its exact origin is impossible to pin down with any specificity. Folklorists didn't begin collecting examples of the text until 1970 or so.
One of the more common ways participants attempt to make her appear is to stand before a mirror in the dark and repeat her name 3 times, there are many variations including chanting more than 3 times, chanting at midnight, spinning around, rubbing one's eyes, running the water, or chanting her name thirteen times with a lit candle. In some versions of the legend, the summoner must say, "Bloody Mary, I killed your baby." In these variants, Bloody Mary is often believed to be the spirit of a young mother whose baby was stolen from her, making her mad with grief, eventually committing suicide. Other versions tell that if one chants her name thirteen times at midnight into a mirror she will appear and the summoner can talk to a dead person until 11:08a.m., when Bloody Mary and the dead person asked to speak to will vanish. Still other variations say that the querent must not look directly at Bloody Mary, but at her image in the mirror; she will then reveal the querent's future, particularly concerning marriage and children. The most common legend is also the most freaky in stories where Mary is supposed to have been wrongly accused of killing her children, the querent might say "I believe in Mary Worth." This is similar to another game involving the summoning of The bell witch in a mirror at midnight. The game is often a test of courage and bravery, as it is said that if Bloody Mary is summoned, she would proceed to kill the summoner in an extremely violent way, such as ripping their face off, scratching their eyes out, cutting their head off, driving them insane, bringing them into the mirror with her or scratching their neck, causing serious injury or death. Some think if she doesn't kill the one who had summoned her then she will haunt them for the rest of their life