Creeping Marsh

At the beginning of each opponent's upkeep that player may sacrifice a permanent, if they don't,
you draw a card.
At the beginning of your upkeep discard a card
or sacrifice Creeping Marsh.
A marsh is a whole world within a world, a different
world, with a life of its own, with its own permanent denizens, its passing visitors, its voices, its sounds, its
own strange mystery.