Cheapest priced copy (Secret Lair Drop): $27.99 at Card Kingdom, near mint, out of stock, their price list as of .
Void Winnower 
Creature — Eldrazi · 11/9 · Mythic · Secret Lair Drop · #1075
Your opponents can't cast spells with even mana values. (Zero is even.)
Your opponents can't block with creatures with even mana values.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
6 printings · $27.99 to $159.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Battle for Zendikar | 17 | Mythic | $29.99 | $49.99 |
| Battle for Zendikar Promos | 17p | Mythic | $32.99 | $74.99 |
| Battle for Zendikar Promos | 17s | Mythic | — | $49.99 |
| Store Championships | 32 | Rare | — | $159.99Out of stock |
| Secret Lair Drop | 1075 | Mythic | $27.99Out of stock | $34.99Out of stock |
| Secret Lair Drop | 2122 | Mythic | — | — |
5 rulings from Wizards of the Coast
- 25 August 2015Effects that increase or reduce the cost to cast a spell don't affect that spell's mana value.
- 25 August 2015The mana value of a face-down creature spell or a face-down creature is 0. Void Winnower will stop face-down creature spells from being cast and face-down creatures from blocking.
- 25 August 2015Yes, your opponent can't even. We know.
- 25 August 2015For 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.
- 25 August 2015For 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. For example, your opponent could cast Endless One (with mana cost {X}) with X equal to 5, but not with X equal to 6.