Tranquil Karst
Land (Rare)

When Tranquil Karst enters the battlefield, you lose 1 life unless you reveal a land card from your hand.

GW, Tap: Add WW, WG or GG to your mana pool.

2: Tranquil Karst becomes a 2/2 green Bear Elf creature until end of turn. It's still a land.

Jason Palck