In Magic the Gathering the Spell Blast card counters target spell and you must pay X where X is the cost of the target spell so does that include the color of the mana in the target spell?
You pay X colourless mana, where X is the converted mana cost of
the target spell. Converted mana cost is just a number, it doesn't
take into account the colours it is counting. So if you were trying
to negate Lightning Bolt, the converted mana cost is '1', meaning
you would pay 1 Blue and 1 colourless for a Spell Blast targeting
it.