Yawgmoth, Lord of Wastes

0: Add three mana of any one color. Put a number of loyalty counters on Yawgmoth equal to the amount of mana in your mana pool.
-4: Create X 4/4 black Zombie creature tokens, where X is the number of Zombies you control.
-15: Exile all non-Zombie creatures, then return them to the battlefield under your control. They are Zombies in addition to their other types.