Calciform Swamp
Land-Plains Swamp (Rare)

(Tap: Add W or B to your mana pool.)

When Calciform Swamp enters the battlefield, you lose 2 life unless you reveal a nonbasic land card from your hand.

WW: Prevent the next 1 damage that would be dealt to target creature or player this turn.

2, Tap: Target land becomes a 3/3 black Rat creature until end of turn. It's still a land.

Douglas Critchlow