Spell Blast
Instant
Counter target spell with mana value X. (For example, if that spell's mana cost is 
, X is 5.)
Call it the thinking mage's version of brute force.
Illustrated by
Tempest#89CommonEnglishLegality
Rulings
Jul 1, 2013
If the target spell has in its mana cost, include the value chosen for that X when determining the value of the in Spell Blast's mana cost. For example, if you wish to counter Volcanic Geyser (a spell with mana cost 
) whose X is 7, you'll need to choose 9 for Spell Blast's X and pay 
.
Jul 1, 2013
Alternative costs, additional costs, cost increases, and cost reductions don't affect a spell's mana value.