Corpse-king Kelias

You may cast Corpse-king Kelias from your graveyard.
Whenever a Zombie you control dies, if it didn't
have a +1/+1 counter on it, return it to the
battlefield under your control with a +1/+1
counter on it.
Whenever a Zombie enters the battlefield, if it
had a +1/+1 counter on it, each opponent
sacrifices a creature and discards a card.