The Druid Oak

+1: Create green 0/0 druid creature token, it enters the battlefield with as many +1/+1 counters as this has progress counters.
0: Delegate three creatures, create a green */* Legendary creature token named The Druid Oak with reach, exile it at the start of your next turn.
-10: You gain an Emblem with "whenever you tap a permanent to produce green mana, gain one additional green mana."