Anchor Plains
Land (Rare)

Anchor Plains enters the battlefield tapped unless you control four or more colorless permanents.

1, Tap: Add UU, UW or WW to your mana pool. Anchor Plains deals 1 damage to you.

1U: Anchor Plains becomes a 1/1 white and blue Shapeshifter Crab creature with flying until end of turn. It's still a land.

Steve Pollack