A Membership Game
Black Magic is an example of a secret rule game.
A secret rule game is a playful, often puzzling group activity where one or a few players know a secret rule that determines what fits or happens in the game, while the rest of the players must figure it out through observation and deduction. The fun lies in the mix of confusion, clever hints, and the "aha!" moment when players crack the code, making these games perfect for sparking laughter and creative thinking in social settings.
Like all secret rule games, Black Magic is played in a group where some, but not all, players know the secret rule.
Black Magic is also an example of a Membership game.
In a Membership game, gameplay revolves around organizing things into groups based on a specific quality. Anything that can be discussed — a person, place, thing, or otherwise — may or may not have that quality. Players who know the secret rule understand the criteria that determine whether something is black magic.
Gameplay in Black Magic revolves around players gathering examples of something that either is black magic, or not.
There are two ways examples can be provided. First, a player who knows the secret rule can volunteer an example, identifying whether it is black magic. When providing examples, it is often helpful to offer two things that are similar in some respects, but only one of which is black magic — the contrast gives the other players something to reason about.
Second, players who don't yet know the rule can suggest something new and ask the knowers whether it is black magic. Knowers respond at the same time, building up a body of examples for the unknowers to deduce from. While questions will almost always be answered with "yes" or "no", there are some cases where the answer may be less concrete, which can give players further clues about the secret rule.
The game ends when all players have figured out the rule and can agree on whether something is black magic reliably. Those players will no longer be able to play that particular game, but there are plenty of other secret rule games to try next.
It's not recommended to play this game in a vehicle setting, such as on a road trip, since being able to see and point to things will lead to a better gameplay experience.
Reveal the secret to Black Magic
A thing is black magic if and only if it is tested immediately after the previous thing tested was black.
One thing to consider when playing Black Magic is what it means for something to be black. It sounds simple, but in practice it can be complicated.
Examples:
Is a Snowman black?
Probably not, even with those eyes made out of coal.
Is a Zebra black?
It's as black as it is white, but somehow it feels like it isn't.
Is a Phone Screen black?
When it's turned off I guess...
Is Barack Obama black?
Is Michael Jackson?
My recommendation is stick to categorizing objects by their most prominent and/or most distinguishing color, and avoid other definitions of 'black.' If you made dozens of multicolored copies of the object in question, and the easiest way to point out the original is "the black one," it's black.