Windbrisk River
Land (Rare)

Windbrisk River enters the battlefield tapped unless you control an enchantment.

Tap: Add W or U to your mana pool.

Sacrifice Windbrisk River: Add W or U to your mana pool.

WU: Windbrisk River becomes a 2/1 white and blue Knight creature until end of turn. It's still a land.

Lars Chippy