# Tapping land for mana with free cast and X in cost

If I have Galvanoth out and the card that is revealed is Skyscribing, am I able to tap lands to pay for the X amount? Would this be any different with Jeleva, Nephalia's Scourge?

• For the second part of your question, are you referring to revealing Jeleva with Galvanoth? or playing skysribing with Jeleva? Commented Nov 14, 2013 at 16:45
• Playing Skyscribing with Jeleva Commented Nov 14, 2013 at 17:12

No, in both cases, you cannot tap additional lands to pay for the X. X, if it's not specified on a card, is always considered to be zero. In both cases, the spell's cost is not being paid for, it's being replaced. Galvanoth and Jeleva aren't saying "Add mana to your mana pool equal to the casting cost", they are replacing the cost altogether. So you can't add anything addional to the spell.

Relevant Gathering rules for Galvanoth:

If the card has an X in its mana cost, you must choose 0 as its value.

In both case, you are casting a card without paying its mana cost, so the answer is the same: The only legal choice for X is 0.

107.3b If a player is casting a spell that has an {X} in its mana cost, the value of X isn’t defined by the text of that spell, and an effect lets that player cast that spell while paying neither its mana cost nor an alternative cost that includes X, then the only legal choice for X is 0. This doesn’t apply to effects that only reduce a cost, even if they reduce it to zero. See rule 601, “Casting Spells.”

There's even a ruling on Galvanoth confirming this:

If the card has an X in its mana cost, you must choose 0 as its value.

When you cast a spell, first you determine what cost you're going to pay from among your options. For example, when casting Force of Will, you choose between {3}{U}{U} and "exile a blue card from your hand and lose 1 life." Effects such as Galvanoth and Jeleva only give you one option, "without paying its mana cost."

For an {X}-cost spell, you choose X and use that choice to set the cost of the spell... but if you're casting the spell without paying {X}, your only legal choice for X is 0.

Once you've made all other decisions about casting the spell (hybrid color choice, phyrexian mana, modal spell modes, targets, etc.), you apply cost increasers (such as Sphere of Resistance), then cost reducers (such as Helm of Awakening), and then finally you apply the effects of Trinisphere. (Note: Your choice for X comes a long time before cost increasers and Trinisphere, so when you're casting your spell for "free," X is still going to remain 0, even if there are a bunch of taxes in play.) Then the spell is cast, and players get priority to do other things.

While you can tap more lands than the mana required to cast the spell, that won't generally do anything -- you'll just be floating mana. It also doesn't help much strategically, since (a) the floating mana is lost as soon as the turn advances to the next step or phase, and (b) you're required* to announce floating mana when you pass priority.

* While you're supposed to announce floating mana every time you pass priority, it's unlikely anyone is going to care if it's obvious that the amount has not changed since the last time you announced it, for example during the resolution of a series of Storm spell copies.

No.

A ruling on gatherer for the Galvanoth says as much:

If the card has an X in its mana cost, you must choose 0 as its value.

X always = 0 for CMC (converted mana cost) when X cannot be tapped for mana. As far as the 2nd question Jeleva's CMC would be 4. (edit) But the X amount paid would thus be 0.

• This does not answer the question asked, and is also incorrect. ({X} counts towards a spell's CMC while that spell is on the stack, although it is considered 0 everywhere else.) Commented Nov 14, 2013 at 20:23
• Every where else is the context of the question and my answer. Commented Nov 14, 2013 at 20:30
• The question has nothing to do with CMC. It's dealing with alternate costs. The question also doesn't ask what Jeleva's CMC would be (you're correct that it's always 4, though), but rather the result of Jeleva's triggered ability casting an {X}-cost spell. Commented Nov 14, 2013 at 20:33
• You need to reread the question its asking about Galvanoths ability with revealed cards... Commented Nov 14, 2013 at 20:35
• Galvanoth doesn't care what the revealed card's CMC is. Jeleva doesn't care what the exiled card's CMC is, nor what her own CMC is. The entire concept of CMC is irrelevant to this question. Commented Nov 14, 2013 at 20:38