Paying X timing

Asked by ElimGarak 6 years ago

Hi, the problem me and my friend are having is that he casts Burn from Within and taps all his lands for it. I answer with Mystic Confluence.

The question is, does he have to "use" all of his mana the moment he casts it or can he wait for responses and then decide how much of his mana pool is going into that spell.

I found this on the mtg wiki:

"the controller of that spell or ability chooses and announces the value of X as part of casting the spell or activating the ability"

Not really sure how to interpret the "announces" part, does he have to pay it or not?

Rhadamanthus says... Accepted answer #1

"Announces" is just being used here for its regular English definition. Your opponent needs to specify what X is when they first cast the spell. They can't change their decision later or "un-pay" any of the costs based on other players' responses.

The casting process has several steps to it. The key thing to know here is that all the decisions (including the value of any X) are made in some of the earlier step and paying costs is the very last step. The spell is only officially "cast" once the costs are actually paid. This is the point where people are allowed to start making responses.

If your opponent wants to get tricky by announcing an X and then tapping more lands to leave some mana floating, it's important to note that they're required to declare how much floating mana there is before passing to see if anyone has responses.

December 8, 2017 4:15 p.m. Edited.