Pinecrest Vents
Land (Rare)

Pinecrest Vents enters the battlefield tapped unless you sacrifice a Beast.

Tap: Add G to your mana pool. If you played a land this turn, Add U to your mana pool instead.

GU: Pinecrest Vents becomes a 2/1 green and blue Elf creature until end of turn. It's still a land.

Jason Schuler