whenever you tap a forest for mana, add an additional g.
+1: put three +1/+1 counters on up to one target noncreature land you control. untap it. it becomes a 0/0 elemental creature with vigilance and haste that's still a land.
−8: you get an emblem with "lands you control have indestructible." search your library for any number of forest cards, put them onto the battlefield tapped, then shuffle your library.
