Thalassa, Verdant Champion

Whenever a land enters the battlefield under an opponent's control, you may put a +1/+1
counter on Thalassa, Verdant Champion.
Lands your opponents control enter the
battlefield tapped.
At the beginning of each player's upkeep, that
player sacrifices a land unless they pay X, where
X is the number of +1/+1 counters on
Thalassa, Verdant Champion.