Question about Plasm Capture
General forum
Posted on Oct. 8, 2015, 1:02 a.m. by Tazmonk
Alright so I have been thinking about Plasm Capture and I found out that when you counter a spell such as Fireball some weird stuff can happen. So basically if a player chooses "X" to be 5 then when Fireball is cast it's converted mana cost is 6 ( 5R ) so when you counter with Plasm Capture you would gain 6 mana on your next precombat main phase. What I want to know is if you say that you would like to cast Fireball for one million mana, but you don't have the mana for it, is it possible to then counter it with Plasm Capture before the game checks if you are able to pay the one million mana? Thus on your next turn giving you one million and one mana.
also, questions should be asked in the Q&A section located at the top of the site
October 8, 2015 1:22 a.m.
DERPLINGSUPREME, that's not correct, from Plasm Capture's gatherer rulings:
4/15/2013 If the countered spell had X in its mana cost, include the value chosen for that X when determining how much mana to add to your pool. For example, if you counter a spell that costs XR with X equal to 5, you'll add six mana to your mana pool.
To answer the openers question: no you can't do that. When casting a spell with X in it's mana cost you can declare any desired value for X but before you get priority and a chance to respond to it, you have to finish the casting process wich includespaying the mana cost.
October 8, 2015 1:24 a.m.
and no you can not cast it for one million if you dont have the mana for it. you must declare and pay the amount of 
at the time of being cast
October 8, 2015 1:25 a.m.
MindAblaze says... #6
That and you can't counter a spell that hasn't been cast.
Aka
You can only legally target a spell on the stack, and you have to pay the cost of a spell before it can end up on the stack.
October 8, 2015 2 a.m. Edited.
Why would you be able to cast a spell with mana do you don't have?
October 8, 2015 3:55 a.m.
Ohthenoises says... #8
So, this is what happens:
Your opponent, as the active player, has priority. First they announce that they are casting Fireball, before Fireball is put on the stack they must select targets and choose a value for X. Once that value is chosen they much pay all costs (including any cost reductions).
Once all of this is done the spell is put on the stack. Then priority is passed to the non-active player, you.
At this point is the first and only time you can cast Plasm Capture.
So no. You don't have an opportunity to cast Counterspell until all costs have been paid.
October 8, 2015 6:08 a.m.
mathimus55 says... #9
What noises said.
Also, is always 0 UNLESS the spell is on the stack. The has to be paid while casting the spell in order to put it on the stack, once the spell gets there then the cmc becomes the new cost with included. Then once the spell resolves and goes to your graveyard returns to 0.
October 8, 2015 10:58 a.m.
Which means both Mistcutter Hydra and Endless One can be cast if Void Winnower is on the opponent's field (hydra for even X cost, endless for odd X cost), but only the hydra can block.
DERPLINGSUPREME says... #2
its reads as converted mana cost. fireball's CMC is ruled at 1, no matter the happenstance, and therefore it would add 1 mana.
October 8, 2015 1:14 a.m.