How do hidden cards work in Riftbound, including: cost to hide vs play, battlefield placement/targeting rules, same-turn play restrictions, and what happens if you lose control of the battlefield?

Ruling: To hide a card costs 1 recycle energy. Playing a card from hidden costs exactly 0 energy (you don't pay the card's energy cost again). You can only hide cards on a battlefield you control, and you cannot play a card from hidden on the same turn you hid it (no exceptions).

Sequence:

• Pay 1 recycle energy to hide a card on a battlefield you control
• Wait until a future turn
• Play the card from hidden for 0 energy cost

Nuances:

• When playing from hidden, any targets/choices must be from that same battlefield if possible
• Cards with global effects (like Zhonya's) still work globally when played from hidden
• Cards that can target any battlefield when played from hand (like Fog of War) can only target their own battlefield when played from hidden
• If you lose control of the battlefield where a hidden card is placed, that hidden card goes to trash
• Even if a reaction chain starts on the same turn you hid a card, you still cannot play it from hidden that turn