Grave-scream Wyrd

Return target creature in a graveyard to the battlefield under your control.
It is a wyrd in addition to its other types.
You lose 4 life.
Living Spell {b}{p/b}: (When you cast this spell,
you may pay its living spell cost; if you do, as it
resolves it enters the battlefield as a creature)
When Grave-scream Wyrd enters the battlefield,
creatures each opponent controls get -X/-X
until end of turn, where X is the number of
creature cards in all graveyards.