| 8/25/2015 |
Effects that increase or reduce the cost to cast a spell don't affect that spell's mana value. |
| 8/25/2015 |
For spells with  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 ) with X equal to 5, but not with X equal to 6. |
| 8/25/2015 |
For creatures on the battlefield with in their mana costs, the value for X is 0. Mistcutter Hydra (a creature with mana cost  ) could block, but Endless One could not. |
| 8/25/2015 |
The 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. |
| 8/25/2015 |
Yes, your opponent can't even. We know. |
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