Zendikar, Realm of Roil

(Whenever a planeswalker enters the battlefield, exile
the current environment, then put the top card
of the environment deck into the command zone)
Whenever a land enters the battlefield, its
controller may pay {3}. If they do, put three
+1/+1 counters on that land. It becomes a 0/ 0
Elemental creature that's still a land.