Mistveil Caves
Land (Rare)

Mistveil Caves enters the battlefield tapped unless you control two or more creatures.

Tap: Add W to your mana pool. Activate this ability only if you control a Plains.

Tap: Add B to your mana pool. Activate this ability only if you control a Swamp.

3: Mistveil Caves becomes a 2/2 black Rogue creature until end of turn. It's still a land.

Christopher Chan