Demeter, of the Harvest

+2: Target creature you control gets the ability, "Tap: Add one mana of any color to your mana pool". (This effect lasts indefinitely)
+1: Add 2 mana of any color to your mana pool.
-11: Untap all lands you control. They become 4/4 creatures until end of turn with haste and trample. They are still lands.