Power of the Forest

If you control a Donna Planeswalker, this spell costs {4} less to cast.
When Power of the Forest enters the battlefield, choose any number of permanents. They become 5/5 spirits with Defender, Flying, and Indestructible until Power of the Forest is exiled or put into your graveyard.
Don't worry, the mists will protect us. Breathe it in, and feel the might of the woods flowing through you. - Donna, Verdant Creator