You may pay 6 life and sacrifice three black creatures rather than pay this spell's mana cost. Flying, trample

Flying, lifelink Pay 7 life: Draw seven cards.

Flying, trample Whenever an opponent searches their library, that player sacrifices a creature of their choice and loses 10 life. Whenever another creature dies, put a +1/+1 counter on Ob Nixilis.

A deck can have any number of cards named Shadowborn Apostle. {B}, Sacrifice six creatures named Shadowborn Apostle: Search your library for a Demon creature card, put it onto the battlefield, then shuffle.