Void Winnower card price from Battle for Zendikar (BFZ) for Magic: the Gathering (MTG) and Magic Online (MTGO).. Official MTG details and rulings for Void Winnower, Creature - Eldrazi from BFZ (17) (English). Read official rules and rulings directly from Magic: The Gathering.
Void Winnower will stop face-down creature spells from being cast and face-down creatures from blocking. For creatures on the battlefield with {X} in their mana costs, the value for X is 0. Mistcutter Hydra (a creature with mana cost {X} {G}) could block, but Endless One could not.. Notes and Rules Information for Void Winnower: Effects that increase or reduce the cost to cast a spell don't affect that spell's mana value. (2015-08-25) For spells with {X} in their mana costs, use the value chosen for X to determine if the spell's mana value is even or not.