A swamp has the innate ability to tap for B in the rules (layer 0).
Urborg, Tomb of Yawgmoth adds the Swamp sub-type to existing lands (layer 4), which allows them to then tap for B. What layer does this ability get added in? It can't be layer 0, since the land isn't a swamp yet. Does it count as existing by layer 4, since that is where the land type is added? Or is it applied in layer 6, where abilities are typically added?
The reasoning comes in involving an effect animating an Urborg while Humility is in play. Despite Humility removing the abilities of the Urborg, the land is still a swamp, since the type is applied in layer 4, before abilities are lost.
If the ability is added in layer 6, then this makes the Urborg dependent on Timestamps as to whether it can tap for mana. So, does Humility always override an Animated Urborg's ability to tap for black, never override the ability (since it's always a swamp), or is it timestamp dependent? (and why)
I had assumed that it was case 1 (always removed the ability), but I can't rationalize that in the layers.
The land gains the ability to tap for B as a result of the type-setting effect that is applied in layer 4. The granting of the ability is an inherent part of what adding the subtype does, per CR 305.7:
305.7. If an effect sets a land’s subtype to one or more of the basic land types, the land no longer has its old land type. It loses all abilities generated from its rules text, its old land types, and any copy effects affecting that land, and it gains the appropriate mana ability for each new basic land type. Note that this doesn’t remove any abilities that were granted to the land by other effects. Setting a land’s subtype doesn’t add or remove any card types (such as creature) or supertypes (such as basic, legendary, and snow) the land may have. If a land gains one or more land types in addition to its own, it keeps its land types and rules text, and it gains the new land types and mana abilities.
So in this case, it becomes a Swamp and gains the ability to tap for B, and also becomes a creature due to the animation effect, in layer 4 (timestamps won't make a difference here) and then loses the ability in layer 6.
The end result depends on timestamps only to determine the creature's power and toughness and whether it still has the abilities (if any) that the animation effect added. To take an example, let's say Urborg has a Genju of the Fens enchanting it.
- If it was animated before Humility entered the battlefield, it's a 1/1 Legendary Land Creature - Swamp Spirit with no abilities.
- If it was animated after Humility entered the battlefield, it's a 2/2 Legendary Land Creature - Swamp Spirit with the shade-pump ability but no other abilities.
Interesting that 305.7 operates somewhat outside of layers, but the result makes sense. Thanks.
The layers system is solely for resolving the interaction of continuous effects. Game rules aren't continuous effects (although continuous effect can modify game rules, such as "target creature can't be blocked until end of turn").
Urborg, Tomb of Yawgmoth adds the Swamp sub-type to existing lands (layer 4), which allows them to then tap for B. What layer does this ability get added in? It can't be layer 0, since the land isn't a swamp yet. Does it count as existing by layer 4, since that is where the land type is added? Or is it applied in layer 6, where abilities are typically added?
The reasoning comes in involving an effect animating an Urborg while Humility is in play. Despite Humility removing the abilities of the Urborg, the land is still a swamp, since the type is applied in layer 4, before abilities are lost.
If the ability is added in layer 6, then this makes the Urborg dependent on Timestamps as to whether it can tap for mana. So, does Humility always override an Animated Urborg's ability to tap for black, never override the ability (since it's always a swamp), or is it timestamp dependent? (and why)
I had assumed that it was case 1 (always removed the ability), but I can't rationalize that in the layers.
Retired EDH - Tibor and Lumia | [PR]Nemata |Ramirez dePietro | [C]Edric | Riku | Jenara | Lazav | Heliod | Daxos | Roon | Kozilek
So in this case, it becomes a Swamp and gains the ability to tap for B, and also becomes a creature due to the animation effect, in layer 4 (timestamps won't make a difference here) and then loses the ability in layer 6.
The end result depends on timestamps only to determine the creature's power and toughness and whether it still has the abilities (if any) that the animation effect added. To take an example, let's say Urborg has a Genju of the Fens enchanting it.
- If it was animated before Humility entered the battlefield, it's a 1/1 Legendary Land Creature - Swamp Spirit with no abilities.
- If it was animated after Humility entered the battlefield, it's a 2/2 Legendary Land Creature - Swamp Spirit with the shade-pump ability but no other abilities.
Retired EDH - Tibor and Lumia | [PR]Nemata |Ramirez dePietro | [C]Edric | Riku | Jenara | Lazav | Heliod | Daxos | Roon | Kozilek
Two Score, Minus Two or: A Stargate Tail
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