The rules may vary somewhat from time to time, but the following is the basic set up. (Rules involving sundry variations may be noted in parentheses.)
The purpose of the game is to contact a spirit through mirror divination. One girl will hold a lit candle, and they all crowd into a bathroom and look into the mirror and switch off the light. As the girls look in the mirror, they say, "Bloody Mary,” three times together. (Or they say “Mary Worth,” “Mary Worthington,” “Mary Whales” three times. Or they say "I Believe in Mary Whales," three times, or alternatively, "Mary Whales, I believe in you." Or another specific phrase may be recited. However, what I first heard about was chanting the name "Bloody Mary.") It must be said without giggling. It must be chanted a specific number of times (usually 3, but it can be 5, 10, 13, 50, 100, etc.). (Sometimes they must turn on the hot water so some steam fogs the mirror.) The spirit in the mirror is often described as either an angry victim of an untimely death or the avenging spirit of a witch.
The version I learned in Maryland was--if everyone in the group does it correctly--the face of a young girl will appear in the mirror, along with their reflections. (I specifically heard that Bloody Mary will appear with blood running down her face from a large cut or scratches in her forehead.)
At this point, the person holding the candle may ask her one question and the answer will be true. It is also possible that the spirit will try to scratch the face of whoever asked the question. However, if nobody asks her a genuinely sincere question, she will be angry, and she will likely reach out and scratch someone on the face, anyway.
If the candle at any time blows out, she will reach out of the mirror and grab someone and drag her inside the mirror. The only way to prevent her from doing that is to flip on the light switch quickly enough.
(However, I also heard in Maryland that if the girls screw up saying the name/phrase, there will be a different problem. If they don’t say the name/phrase altogether correctly--or don’t say the name/phrase altogether the correct number of times--the spirit will not appear. No one I spoke to in Maryland said that the spirit showed up.)
In some versions, the face of an old gray or white haired woman appears. She may or may not have a bloodied face.
(Much later, I learned about another version in which the girls--after reciting the name three times—say loudly, “I KILLED YOUR KID!” or “I KILLED YOUR SON!” or even “I stole your baby, Bloody Mary!” while staring into the mirror in a darkened bathroom. In this case, a woman might appear weeping tears of blood.)
The above is a synthesis of what I had read in random folklore books and from what I had gotten from a few scattered conversations about urban legends in college.
Some Maryland Lore:
In the summer of 1993, I was with my husband at the mom and pop video rental store, Budget Video, on Frederick Road in Catonsville. It's a Dunkin Donuts now.
This particular video rental store was right up our alley; not only did it have the new releases, but it also had a nice collection of SF, Fantasy, Horror, and Action/Adventure videos, including several obscure titles. (It was from this location that I rented out George Romero's little known film, Season of the Witch, 1972.)
My husband was looking in the SF section. I was browsing in Horror. Two girls about age 10 or so bounced over and were looking at titles.
Girl #1 picked up a video and said, "Oooh, look--Candyman! It was good. Wanna get it?!"
Girl #2, looking through the boxes: "No. I saw that already. Let's find something else."
They discuss something about other movies and what section they would check out next. To be honest, I wasn't paying much attention to them other than they were about six inches from my elbow.
They were about to move on when Girl #1 said: "Hey--you know that game where you say 'Bloody Mary' five times and she comes out of the mirror and scratches you? It doesn't work."
The pair scampered off to another section.
I had been startled to overhear the name, "Bloody Mary," in their conversation, and even more startled to realize I had accidentally collected some evidence of this game still being played here in Maryland.
If you are interested in more about the spirit of Bloody Mary, click on one of the links below.
Who is the Spirit in the Mirror?
Copyright 2016 Myth Woodling
Who is this Mary in the Mirror?
Mary the Witch: Factual Basis?
Stories about Playing the Game
Mary in the Maryland Graveyard
More about Bloody Mary
Folktales
"Yet Another Wicca..." home page