Yorick, Shepherd of Souls

When Yorick enters the battlefield, create three 3/1 black Ghoul creature tokens with haste.
Whenever a creature you don't control dies, put a 3/1 black Ghoul creature token with haste onto the battlefield.
Sacrifice 6 creatures: Put a 6/6 black Maiden of the Mist creature token with hexproof and lifelink onto the battlefield. You can only control one Maiden of the Mist at a time.