Uncork it: your king cannot be captured for your opponent's next 2 turns, and every piece of yours standing beside him cannot be captured for those 2 turns either.
You draft Bottled Courage in either mode. Activated: you choose when to use it, and using it is your move for that turn.
As a item card, it is a one-use consumable, drafted in either mode.
“Label says courage. Chemically, it is mostly stubbornness.”