Grass-Crypt
Land (Rare)

Grass-Crypt enters the battlefield tapped unless you pay 3 life.

G, Tap: Add BB to your mana pool.

B, Tap: Add GG to your mana pool.

BG: Grass-Crypt becomes a 2/1 green and black Elf creature until end of turn. It's still a land.

Greg Schuler