At the beginning of each player's upkeep, that player sacrifices a non-Zombie creature. At the beginning of the end step, if no creatures are on the battlefield, sacrifice Call to the Grave.
Call to the Grave [Magic 2012]
Main Store - 120 Newkirk Road
Pickup available,usually ready in 1 hour
120 Newkirk Road Unit 26 Richmond Hill ON L4C 9S7 Canada