Btukfyl

Escaped Shapeshifter has an interesting functional erratum.

The oracle text reads:

As long as an opponent controls a creature with flying not named Escaped Shapeshifter, Escaped Shapeshifter has flying. The same is true for first strike, trample, and protection from any color.

The part in bold ("not named Escaped Shapeshifter") is not printed on the card.

I presume this text was added to avoid rules complications. So, what happens if it isn't there? Note, the added text can be circumvented by cards like Sakashima the Impostor that can copy creatures without copying the name (though this may not have been possible at the time the text was added).

I guess this is the problem case: both players control an Escaped Shapeshifter. One player plays a creature with flying. Now both shapeshifters fly. The flying creature leaves the battlefield. Do the shapeshifters still fly?

(I would also be interested in other problem cases that I might not be seeing.)

There are two situations that are affected in meaningful ways by this wording change.

In the first situation, two players each have an Escaped Shapeshifter, then one plays a creature with one of the named abilities (e.g. flying). Under the old ruling, both Escaped Shapeshifters would gain flying. With the new wording, only the Shapeshifter opposed to the creature that naturally has flying would gain flying. There is nothing really problematic rules-wise in this situation, but I suspect that the behavior with the old wording was a worse fit for the flavor of the card.

The second situation is the one you describe, where you start with the same creatures as in the first scenario, and then the creature that naturally has flying goes away. With the old wording and the current rules, both Shapeshifters would lose flying. With the new wording, it is pretty clear that the opposing Shapeshifter would lose flying. I believe that this is the problematic scenario, because under the old wording it's not obvious to most players what would happen.

To understand why the abilities would be lost under the old wording, we have to delve deep into the rules regarding the interaction of continuous effects. In Magic, evaluating the outcome of effects like this uses what is commonly known as the "layer system". In this case, the layers themselves are less important because the ability in question only operates on one layer: "Layer 6: Ability-adding effects, ability-removing effects, and effects that say an object can't have an ability". When applying multiple effects in the same layer, two subrules of that section apply:

• 613.6. Within a layer or sublayer, determining which order effects are applied in is usually done using a timestamp system. An effect with an earlier timestamp is applied before an effect with a later timestamp.




• 613.7. Within a layer or sublayer, determining which order effects are applied in is sometimes done using a dependency system. If a dependency exists, it will override the timestamp system.

This dependency system is the way the rules rigorously represent the idea of "one Shapeshifter gains flying because the other Shapeshifter gains flying". The rule for deciding whether the dependency system applies is 613.7a:

An effect is said to "depend on" another if (a) it's applied in the same layer (and, if applicable, sublayer) as the other effect (see rules 613.1 and 613.3); (b) applying the other would change the text or the existence of the first effect, what it applies to, or what it does to any of the things it applies to; and (c) neither effect is from a characteristic-defining ability or both effects are from characteristic-defining abilities. Otherwise, the effect is considered to be independent of the other effect.

Using the old wording, we can see a difference in how this would be evaluated in the two situations:

1. Let's call the Shapeshifter controlled by the player with the flying creature Shapeshifter A, and the one controlled by the opponent Shapeshifter N. We can see that there is a dependency here: (a) they are both in the same layer; (b) if Shapeshifter N's effect is applied first then it gets flying from the creature that naturally has flying, which changes the outcome of applying Shapeshifter A's effect; and (c) the ability is not a characteristic-defining ability. The same is not true the other way around: applying Shapeshifter A's effect first will do nothing, which will have no effect on what Shapeshifter N's effect will do.




2. In this case, if you apply either Shapeshifter's effect first, it gains no abilities because none of the opponent's creatures have any of the named abilities (yet), which means that it doesn't change what the other Shapeshifter's effect does. So, this fails the second condition and there is not a dependency.

In the first situation, we would apply Shapeshifter N's effect first, and then apply Shapeshifter A's effect, and in the end both would have flying. In the second situation, we would apply the effects in timestamp order, which depends on when they entered the battlefield, and no matter what that order is they would not gain flying.