Use once as a free action: flip a fair coin. Heads: your queen cannot be captured during your opponent's next 2 turns. Tails: nothing but a sheepish flash on your king.
You draft Evil Eye Bead in either mode. Free action: you choose when to use it, and it resolves without costing your turn.
As a item card, it is a one-use consumable, drafted in either mode.
“Blue glass, unblinking, pinned to the royal hem.”