I was brushing up on layers today. While reading through the examples in the copy of the CR I downloaded from a post here, I found an example that confused me. It read as follows:
“Example: Svogthos, the Restless Tomb, is on the battlefield. An effect that says Until end of turn, target land becomes a 3/3 creature thats still a land is applied to it (layers 4 and 7b). An effect that says Target creature gets +1/+1 until end of turn is applied to it (layer 7c), making it a 4/4 land creature. Then while you have ten creature cards in your graveyard, you activate Svogthoss ability: Until end of turn, Svogthos, the Restless Tomb becomes a black and green Plant Zombie creature with This creatures power and toughness are each equal to the number of creature cards in your graveyard. Its still a land. (layers 4, 5, and 7b). It becomes an 11/11 land creature. If a creature card enters or leaves your graveyard, Svogthoss power and toughness will be modified accordingly. If the first effect is applied to it again, it will become a 4/4 land creature again.”

(Excerpt From: DCI. “Magic Comprensive Rules.” Ryan Stapleton. iBooks.
This material may be protected by copyright.)

Why is Svogthos' new power and toughness after activating its ability applied in layer 7b and not 7a? The way it's worded in the card's text looks like it gives it a static characteristic defining ability until EOT. Is it only considered a CDA if it's a static ability printed directly on the card and therefore doesn't have to be activated, like in the case of Tarmogoyf?

Edited Kenny Dolson (March 8, 2016 05:28:07 AM)

To be a characteristic-defining ability, it has to fit 5 criteria (from 604.3a):

(1) It defines an object’s colors, subtypes, power, or toughness
(2) it is printed on the card it affects, it was granted to the token it affects by the effect that created the token, or it was acquired by the object it affects as the result of a copy effect or text-changing effect
(3) it does not directly affect the characteristics of any other objects
(4) it is not an ability that an object grants to itself
(5) it does not set the values of such characteristics only if certain conditions are met

Svogthos's ability fit 1, since it defines the power, toughness, subtypes, and colors of it. It fit 3, since it's not affecting any other object.

However, it fails 2, since it's being given it by the resolution of an activated ability; it's not printed on the card, it's not given to it when the token was made, and was not acquired due to a copy or text-changing effect. It also fails 4, since it's ability that it granted to itself due to its activated ability.

Since it does not fit all 5 criteria, it's not a CDA, and it will be applied in layer 7b, not 7a.

Nathan Long
Magic Rules NetRep

Edited Nathan Long (March 10, 2016 11:15:21 PM)