Sulfurous Fortress
Land-Plains Swamp (Rare)

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

Sulfurous Fortress enters the battlefield tapped unless you sacrifice a colorless permanent.

BB, Tap, Sacrifice Sulfurous Fortress: Put a -1/-1 counter on target creature.

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

Ron Nielsen