Magic the Gathering: What happens when I copy an "X" cost spell?

Question

Example: I play a spell with "X" in the cost, then copy it with "Twincast".

Does the copy have the same effect as the amount I paid "X" for, or do I have to pay "X" again for the copy?

Answer 1

Copying a spell will copy its mana cost. So if you twincast a fireball with X=9, your copy will have mana cost 10 (X=9 +Red mana).

Some effects that allow you to play a spell without paying its mana cost (like mind's desire) will count X as zero. However, when you copy a spell on the stack, you will copy every aspect of the game, that is why twincast mentions that you can choose new targets for the copy (otherwise it would have the same targets).

Answer 2

x becomes 0 zero when the copy goes on the stack, you are  not playing the spell and you cannot 'define' x.

Answer 3

When you copy a spell you copy the spell, not the card.  So if you cast the X spell for 5, then you are copying the spell at 5.

X is defined while the spell is on the stack, then you copy that spell which already has X defined so you are copying the X as well. MAke sense?

Answer 4

Actually, X is always zero on the stack. It doesn’t matter how much it was set to originally, the new copy of the spell would forget all instances of its previous existence. Because you can’t pay the mana cost for spells copied with Twincast, X is zero. X is always zero.

For example: I play Draining Whelk on a 13BB-costing Profane command. The spell gets countered, but the whelk would only get two measly counters, not 15, because X is on the stack, and X is always zero on the stack.

Because of this, I don’t recommend you twincasting any 6+ mana Mind Springs. You’ll draw the exact same amount of cards without using the Twincast. However, using Twincast on Ancestral Visions is a great idea. Experiment with it.