Grexuhoon, the Creeping Bog

Grexuhoon enters the battlefield tapped unless
you pay 2 life.
Whenever a land enters the battlefield under an opponents control you may pay {1}. If you do,
add a swamp counter to Grexuhoon.
{t}: Add {b} for each swamp counter on Grexuhoon.
The slime washes over the lands like an
unstopping tide.