Sol'kanar, Terror of Khone

Trample
Whenever a creature enters the battlefield under
your opponents control, that player sacrifices
that creature unless they put X +1/+1 counters
on Sol'kanar, Terror of Khone where X is that
creature's power.
What was once a benevolent spirit of the forest has been corrupted by Geyadrone to hunt her enemies and forge
her unholy citadel of bones.