Unearthly Tremors

When Unearthly Tremors enters the battlefield,
it deals 2 damage to each creature without flying.
Landfall - Whenever a land enters the battlefield
under your control, you may pay {1}{r}. If you do,
create a red Hydra creature token with "This
creature's power and toughness are each equal
to the number of Hydra's you control."