If you are unlucky enough to summon Bloody Mary, there’s no real standard of what you’ll see. By some accounts, she’s hideously mutilated but in others she is beautiful but bloody—more commonly though—every aspect of her appearance is vague. There’s even versions where she was a witch burned at the stake in Salem. In some legends, she’s connected to a cult. But where she comes from and what she looks like is less important than the ritual that summons her.

• Dr. Emily Zarka