when a card has double xx and a mountain, what does it mean?
when a card has double xx and a mountain, what does it mean?
Well, you know how 1 X in a card's cost means you announce a value for 'X' when you cast the card, and then replace all instances of X with that number, right?
For example, when you cast Banefire and you announce '5' as the value for X, then the cost of Banefire becomes 5R, or 5 colorless mana and one red mana. Banefire will then deal 5 damage when it resolves.
It works exactly the same with XX in a card's cost, except that there's two X's. You'll still announce one value for "X," but you'll have to pay that value twice. So, if you cast Bonfire of the Damned and you choose for X to be 4, then you'll pay 44R, or 8 colorless mana and one red mana. Then, Bonfire of the Damned will deal 4 damage to target player and all creatures he or she controls, assuming it resolves successfully.
This is why Bonfire's Miracle cost is only XR (instead of XXR when cast normally). This way, if you cast it for its Miracle cost, choosing 4 as the value of X will result in a casting cost of XR, or a total of 5 mana (4 colorless and one red mana).
Does that all make sense? I tried to simplify it as much as possible. If you need any more examples or clarification, feel free to say so.
I'll repeat it again, just in case it helps. Whenever "X" appears in a spell's casting cost, that value is equal to whatever you choose as you cast the spell. After you've chosen a value, replace all instances of "X" in the spell's casting cost and card text with the value you've chosen.