■ Once per turn , when you put a card into your mana zone , you may turn it face down . (A face down card in your mana zone is treated as a colorless card with a mana number of 1. Its owner may look at them at any time.) (Whenever another D2 Field is put, destroy this D2 Field .) Denjara Switch : Whenever you put a Zenith creature , you may turn this D2 Field upside down for the rest of the game . If you do, untap all face down cards in your mana zone .