Undefined X

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I use Vesuvan Shapeshifter to copy (via morph) a face-up Bane of the Living. The board-wipe ability triggers, with an undefined X. Intuitively I would guess X to default to zero, but I cannot find a rule in 107.3 that supports that conclusion:

107.3. Many objects use the letter X as a placeholder for a number that needs to be determined. Some objects have abilities that define the value of X; the rest let their controller choose the value of X.

107.3a. If a spell or activated ability has a mana cost, alternative cost, additional cost, and/or activation cost with an {X}, [-X], or X in it, and the value of X isn't defined by the text of that spell or ability, the controller of that spell or ability chooses and announces the value of X as part of casting the spell or activating the ability. (See rule 601, "Casting Spells.") While a spell is on the stack, any X in its mana cost equals the announced value. While an activated ability is on the stack, any X in its activation cost equals the announced value.

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."

107.3c. If a spell or activated ability has an {X}, [-X], or X in its cost and/or its text, and the value of X is defined by the text of that spell or ability, then that's the value of X while that spell or ability is on the stack. The controller of that spell or ability doesn't get to choose the value. Note that the value of X may change while that spell or ability is on the stack.

107.3d. If a cost associated with a special action, such as a suspend cost or a morph cost, has an {X} or an X in it, the value of X is chosen by the player taking the special action as he or she pays that cost.

107.3e. Sometimes X appears in the text of a spell or ability but not in a mana cost, alternative cost, additional cost, or activation cost. If the value of X isn't defined, the controller of the spell or ability chooses the value of X at the appropriate time (either as it's put on the stack or as it resolves).

107.3f. If a card in any zone other than the stack has an {X} in its mana cost, the value of {X} is treated as 0, even if the value of X is defined somewhere within its text.

107.3g. All instances of X on an object have the same value at any given time.

107.3h. Some objects use the letter Y in addition to the letter X. Y follows the same rules as X.



(a-c) do not apply because this is neither a spell or activated ability. (It is a triggered ability with an undefined X)
(d) applies to Bane of the Living, but not to Vesuvan Shapeshifter; there was no X in the cost of the special action to turn VS face-up.
(e) looks like it applies but implies that I would be able to choose any value of X that I wanted upon resolution (as funny as this would be, it's a bit absurd)
(f-h) are irrelevant.


Am I missing something?
Yes.  You're overlooking the fact that you paid Vesuvan Shapeshifter's morph cost to flip it over, not Bane of the Living's.  The ability still triggers, but it looks for what you paid for X.  You didn't pay for X.  Therefore, X is 0.

Rules Advisor

I don't see the rules support for that conclusion. Frankly, now that I look at the rules for X costs, I don't see how Bane of the Living is even supposed to work, given that Morph's not an activated ability. If you turned a Bane of the Living face-up with X=5, turned it face-down again, then broke it open, wouldn't the value of X still be 5 since a value was chosen and it's still the same object?

Edit: To be clear, since isn't an activation cost, I don't see the rules support that the triggered ability uses the value for X chosen when the morph cost was paid.
Rules Advisor
107.2. If anything needs to use a number that can’t be determined, either as a result or in a calculation, it uses 0 instead.
107.2. If anything needs to use a number that can’t be determined, either as a result or in a calculation, it uses 0 instead.



If this is the rule I'm supposed to abide by in this situation, can you give me an example for when I would use 107.3e? Otherwise, I don't understand how I'm supposed to know the difference between "undefined and can be determined" and "undefined but can't be determined".
If you turned a Bane of the Living face-up with X=5, turned it face-down again, then broke it open, wouldn't the value of X still be 5 since a value was chosen and it's still the same object?



I...would actually like to know the answer to this as well. (For the sake of argument, assume that Bane has a bunch of +1/+1 counters on it so that it never dies during these processes)
107.2. If anything needs to use a number that can’t be determined, either as a result or in a calculation, it uses 0 instead.



If this is the rule I'm supposed to abide by in this situation, can you give me an example for when I would use 107.3e? Otherwise, I don't understand how I'm supposed to know the difference between "undefined and can be determined" and "undefined but can't be determined".


Example, where X is defined: Accelerated Mutation
If there is no permanent under your control AM can't determine X and treats it as 0 as per 107.2

Example, where X isn't defined but chosen as per 107.3e: Plunge into Darkness
If you turned a Bane of the Living face-up with X=5, turned it face-down again, then broke it open, wouldn't the value of X still be 5 since a value was chosen and it's still the same object?



I...would actually like to know the answer to this as well. (For the sake of argument, assume that Bane has a bunch of +1/+1 counters on it so that it never dies during these processes)


The thing you choose the value of X for is the cost to end the morph effect. This morph effect. Not another, that the permanent might be under at a later time.

I've been searching the Comp Rules for a while and have to agree, that there seems to be nothing to support how Bane of the Living is supposed to work.


I'm not sure I understand what the problem is.
107.3d If a cost associated with a special action, such as a suspend cost or a morph cost, has an {X} or an X in it, the value of X is chosen by the player taking the special action as he or she pays that cost.

707.11. If a face-down permanent would have an “As [this permanent] is turned face up . . .” ability after it’s turned face up, that ability is applied while that permanent is being turned face up, not afterward.

Am I missing something?

If I steal a hundred dollar from a loot of one thousand, people might notice;

If I steal a hundred dollar from a loot of one million, I might get away with it;

If I wish to steal even more and still go unnoticed, I need to make the loot bigger.

 

Now you know why taxes always go up.

 

Looting: ''the plundering of public assets by corrupt or greedy authorities'' (Wikipedia)

The thing you choose the value of X for is the cost to end the morph effect. This morph effect. Not another, that the permanent might be under at a later time.

Confirmed:
702.35d If you have priority, you may turn a face-down permanent you control face up. (...) The morph effect on it ends...

If I steal a hundred dollar from a loot of one thousand, people might notice;

If I steal a hundred dollar from a loot of one million, I might get away with it;

If I wish to steal even more and still go unnoticed, I need to make the loot bigger.

 

Now you know why taxes always go up.

 

Looting: ''the plundering of public assets by corrupt or greedy authorities'' (Wikipedia)

I'm not sure I understand what the problem is.
107.3d If a cost associated with a special action, such as a suspend cost or a morph cost, has an {X} or an X in it, the value of X is chosen by the player taking the special action as he or she pays that cost.

707.11. If a face-down permanent would have an “As [this permanent] is turned face up . . .” ability after it’s turned face up, that ability is applied while that permanent is being turned face up, not afterward.

Am I missing something?


The problem is, that there is nothing in the rules that lets the trigger determine what the value of X was for the morph cost.
The problem is, that there is nothing in the rules that lets the trigger determine what the value of X was for the morph cost.

 Maybe those 2 rules can help, though I'm not sure what to think about it.
611.2d If a resolving spell or ability that creates a continuous effect contains a variable such as X, the value of that variable is determined only once, on resolution. See rule 608.2g.

608.2g If an effect requires information from the game (such as the number of creatures on the battlefield), the answer is determined only once, when the effect is applied. If the effect requires information from a specific object, including the source of the ability itself or a target that’s become illegal, the effect uses the current information of that object if it’s in the public zone it was expected to be in; if it’s no longer in that zone, or if the effect has moved it from a public zone to a hidden zone, the effect uses the object’s last known information. If an ability states that an object does something, it’s the object as it exists—or as it most recently existed—that does it, not the ability.


611.2d and 608.2g certainly apply to the trigger, but the game doesn't know where to look to determine X.

The only rule that I can find that might let the game determine X is

107.3g All instances of X on an object have the same value at any given time.

But the trigger is a different object from the Bane of the Living. And face up, the X in the morph cost is treated as 0, no matter what you chose for it to end the morph effect.

If the trigger specifically referenced the morph cost, then it would be clear. Like
"When Bane of the Living is turned face up, all creatures get -X/-X until end of turn, where X has the same value you chose for the morph cost."


Or if the two abilities were considered linked, but none of the definitions for linked abilities apply.

The reasoning given in the gatherer ruling is not satisfying at all:
10/4/2004 The X in the ability has the same value as the X paid in the Morph ability. This is pretty easy to derive since there is no other source of X.