Mistveil Cavern
Land (Rare)

Mistveil Cavern enters the battlefield tapped unless you control an enchantment.

1, Tap: Add WW, WB or BB to your mana pool. Mistveil Cavern deals 1 damage to you.

1W: Mistveil Cavern becomes a 0/4 white and black Spirit creature with defender until end of turn. It's still a land.

Jesper Moeller