WTF is a state trigger? (Dark Depths)

[lordofthepit]

Edit: Before anyone gives me a LMGTFY, I went ahead and searched the comprehensive rules and found the following. Apologies for not doing this earlier.


603.8. Some triggered abilities trigger when a game state (such as a player controlling no permanents of a particular card type) is true, rather than triggering when an event occurs. These abilities trigger as soon as the game state matches the condition. They'll go onto the stack at the next available opportunity. These are called state triggers. (Note that state triggers aren't the same as state-based actions.) A state-triggered ability doesn't trigger again until the ability has resolved, has been countered, or has otherwise left the stack. Then, if the object with the ability is still in the same zone and the game state still matches its trigger condition, the ability will trigger again.

/end edit. Still interested in how these scenarios play out.

Edit #2: Looks like Skeggi dug up the Comprehensive Rules for me, but I ninja-edited and posted this up before he put up the comprehensive rules! So :tongue: to you (thanks though!).


When Dark Depths has no ice counters on it, sacrifice it. If you do, put a legendary 20/20 black Avatar creature token with flying and "This creature is indestructible" named Marit Lage onto the battlefield.


7/15/2006: Dark Depths's last ability is a state trigger. It will not trigger again while the ability is on the stack, but if the ability is countered and Dark Depths is still on the battlefield with no ice counters on it, it will trigger again immediately.

If I understand correctly, when you remove the last counter on Dark Depths (for instance, with Vampire Hexmage), the condition for this "state trigger" is met, and you sacrifice it. There is an intervening if clause that says if Dark Depths is sacrificed in this manner, you get a Marit Lage token.

However, since the trigger is worded "when Dark Depths has no ice counters on it", rather than "when you remove the last counter", if the triggered ability is somehow countered, it will trigger again immediately. For example:

1) Player A activates Vampire Hexmage's ability, targeting his Dark Depths.
2) Both players pass priority, (1) resolves.
3) Dark Depths' state trigger goes on the stack.
4) Player B uses Stifle to target state trigger (3). Don't ask me why he didn't Stifle Vampire Hexmage's ability instead.
5) State trigger (3) is countered by (4).
6) Does Dark Depths' state trigger immediately go on the stack again? If so, why weren't there infinite state triggers on the stack, since the condition is always met? Is there some condition governing when a state trigger can be put on a stack?

Here's another example; basically, I want to know if I can beat Dark Depths with Wasteland, even after I allow the Hexmage ability to resolve.
1) Player A activates Vampire Hexmage's ability, targeting his Dark Depths.
2) Both players pass priority, (1) resolves.
3) Dark Depths' state trigger goes on the stack.
4) Player B uses Wasteland to target Dark Depths, which currently has no ice counters. Don't ask me why he didn't Wasteland the Depths in response to (1), I don't care. :mad:
Does the state trigger go back on the stack at this point since the condition is "still met"? If so, then (a):
5a) Dark Depths' state trigger goes on the stack, above the Wasteland trigger.
6a) Player A gets his Marit Lage.
7a) Wasteland activated ability fizzles, since Dark Depths is no longer a legal target.
8a) Dark Depths state trigger from (3) fizzles (not sure this is the correct term here).
If not, then (b):
5b) Wasteland's activated ability destroys Dark Depths.
6b) Dark Depths state trigger (the sacrifice part fizzles). Since the if condition is no longer met, player A does not get a Marit Lage token.

How do these cases with two Hexmages play out?

Case #1
1) Player A activates Vampire Hexmage's ability, targeting his Dark Depths.
2) Player B activates Wasteland in response, with (1) still on the stack.
3) Player A activates a second Vampire Hexmage's ability, targeting his Dark Depths, with (1) and (2) still on the stack.
4) Both players pass priority until the stack is cleared.

Case #2
1) Player A activates Vampire Hexmage's ability, targeting his Dark Depths.
2) Both players pass priority, (1) resolves.
3) Dark Depths' state trigger goes on the stack.
4) Player B activates Wasteland in response, with (3) still on the stack.
5) Player A activates a second Vampire Hexmage's ability, targeting his Dark Depths, with (3) and (4) still on the stack.
6) Both players pass priority until the stack is cleared.

[Skeggi]

Bold text explains alot.


603.8. Some triggered abilities trigger when a game state (such as a player controlling no permanents of
a particular card type) is true, rather than triggering when an event occurs. These abilities trigger as
soon as the game state matches the condition. They‘ll go onto the stack at the next available
opportunity. These are called state triggers. (Note that state triggers aren‘t the same as state-based
actions.) A state-triggered ability doesn‘t trigger again until the ability has resolved, has been
countered, or has otherwise left the stack. Then, if the object with the ability is still in the same zone
and the game state still matches its trigger condition, the ability will trigger again.

Example: A permanent‟s ability reads, “Whenever you have no cards in hand, draw a
card.” If its controller plays the last card from his or her hand, the ability will trigger once and won‟t trigger again until it has resolved. If its controller casts a spell that reads
“Discard your hand, then draw that many cards,” the ability will trigger during the spell‟s
resolution because the player‟s hand was momentarily empty.

Edit: this is how I think it plays out:


1) Player A activates Vampire Hexmage's ability, targeting his Dark Depths.
2) Both players pass priority, (1) resolves.
3) Dark Depths' state trigger goes on the stack.
4) Player B uses Stifle to target state trigger (3). Don't ask me why he didn't Stifle Vampire Hexmage's ability instead.
5) State trigger (3) is countered by (4).
6) Does Dark Depths' state trigger immediately go on the stack again?
Yes.


If so, why weren't there infinite state triggers on the stack, since the condition is always met? Is there some condition governing when a state trigger can be put on a stack?
Because it only places itself on the stack if there isn't already an instance of the same trigger on the stack:


A state-triggered ability doesn‘t trigger again until the ability has resolved, has been countered, or has otherwise left the stack.



Here's another example; basically, I want to know if I can beat Dark Depths with Wasteland, even after I allow the Hexmage ability to resolve.
1) Player A activates Vampire Hexmage's ability, targeting his Dark Depths.
2) Both players pass priority, (1) resolves.
3) Dark Depths' state trigger goes on the stack.
4) Player B uses Wasteland to target Dark Depths, which currently has no ice counters. Don't ask me why he didn't Wasteland the Depths in response to (1), I don't care. :mad:
Does the state trigger go back on the stack at this point since the condition is "still met"? If so, then (a):
No, there's already an instance on the stack.



If not, then (b):
5b) Wasteland's activated ability destroys Dark Depths.
6b) Dark Depths state trigger (the sacrifice part fizzles). Since the if condition is no longer met, player A does not get a Marit Lage token.
Looks correct to me.



Case #1
1) Player A activates Vampire Hexmage's ability, targeting his Dark Depths.
2) Player B activates Wasteland in response, with (1) still on the stack.
3) Player A activates a second Vampire Hexmage's ability, targeting his Dark Depths, with (1) and (2) still on the stack.
4) Both players pass priority until the stack is cleared.
(I write down stacks chronologically: from left to right, but they resolve from right to left)

Stack: Hexmage <= Wasteland <= Hexmage. Second Hexmage resolves, Dark Depths' state trigger triggers. Stack now: Hexmage <= Wasteland <= Dark Depths. Dark Depths triggers resolves, sacrifices Dark Depths and makes token. Wasteland is countered because there is no legal target, Hexmage is countered because there is no legal target.



Case #2
1) Player A activates Vampire Hexmage's ability, targeting his Dark Depths.
2) Both players pass priority, (1) resolves.
3) Dark Depths' state trigger goes on the stack.
4) Player B activates Wasteland in response, with (3) still on the stack.
5) Player A activates a second Vampire Hexmage's ability, targeting his Dark Depths, with (3) and (4) still on the stack.
6) Both players pass priority until the stack is cleared.
Stack from point 3 onward: Dark Depths <= Wasteland <= Hexmage. Hexmage removes 0 counters from Dark Depths (Dark Depths does not trigger again because there is still an instance of the trigger on the stack, removing 0 counters from Dark Depths does not change this). Wasteland destroys Dark Depths. Dark Depths 'if' condition is not met and there will be no token.

[thefringthing]

If I understand correctly, when you remove the last counter on Dark Depths (for instance, with Vampire Hexmage), the condition for this "state trigger" is met, and you sacrifice it. There is an intervening if clause that says if Dark Depths is sacrificed in this manner, you get a Marit Lage token.The clause to which you refer is not an "intervening 'if' clause". Rule 603.4 describes these clauses:

603.4. A triggered ability may read “When/Whenever/At [trigger event], if [condition], [effect].” When the trigger event occurs, the ability checks whether the stated condition is true. The ability triggers only if it is; otherwise it does nothing. If the ability triggers, it checks the stated condition again as it resolves. If the condition isn’t true at that time, the ability is removed from the stack and does nothing. Note that this mirrors the check for legal targets. This rule is referred to as the “intervening ‘if’ clause” rule. (The word “if” has only its normal English meaning anywhere else in the text of a card; this rule only applies to an “if” that immediately follows a trigger condition.