Twin Greater Sign of Sealing behavior

[Auerkan]

G.Sign of Sealing from SpC bars object/door from being opened except for breaking, and if its broken explodes by up to 20d6 damage, but can be disarmed with Disable Device. Twin Spell says effects that would not otherwise stack become redundant. Does it mean that Twin GSS needs two DD checks and can explode for two instances of damage?

[Duke of Urrel]

G.Sign of Sealing from SpC bars object/door from being opened except for breaking, and if its broken explodes by up to 20d6 damage, but can be disarmed with Disable Device. Twin Spell says effects that would not otherwise stack become redundant. Does it mean that Twin GSS needs two DD checks and can explode for two instances of damage?

You have asked a very good question!

Everybody should agree that if you have Disable Device skill and you perform two actions to disarm a Twinned Greater Sign of Sealing (at least two full-round actions, or maybe two actions of 2d4 rounds each), you can make two Disable Device checks, and if they both succeed at DC 31, you deactivate both spells. However, reasonable people may disagree about what happens the first time you make a Disable Device check that fails by five or more.

This failure must trigger at least one explosion that deals 1d6 Hit Points of damage per caster level in a 30-foot radius. But should it trigger two explosions at once?

I don't know the answer, and I would recommend that you talk to your dungeon master about this. However, I think it's worth thinking through the consequences of both options before you choose between them.


1. Suppose you decide that one failed Disable Device check triggers only one explosion.

If you decide that one failed Disable Device check triggers only one explosion, I think you also must accept that if you trigger this explosion with your first Disable Device check, you have deactivated only one of the two Twinned Greater Signs of Sealing. The other one is still in effect. So if you survive the explosion, you still have to make a second Disable Device check to deactivate the second Twinned Greater Sign of Sealing. If you fail a second time, you trigger a second explosion.

You don't have this problem if your first Disable Device check succeeds and your second one fails. In this case, your first Disable Device check deactivates one Twinned Greater Sign of Sealing successfully but leaves the other one still in effect. Thus, when your second Disable Device check fails, you trigger an explosion that deals 1d6 Hit Points of damage per caster level in a 30-foot radius. After the smoke clears, the warded object or space is no longer protected, because both Greater Signs of Sealing have been expended.


2. Suppose you decide that one failed Disable Device check triggers two explosions at once.

If you decide that one failed Disable Device check triggers two explosions at once, your success is always either all or nothing. Thus, it makes no difference whether you trigger a Twinned Greater Sign of Sealing with your first Disable Device check or your second one. In either case, you trigger two explosions at once, but after the smoke clears, the warded object or space is no longer protected, because both Greater Signs of Sealing have expended.


Post-Script: Here's a weird thought. Suppose a Twinned spell creates the possibility of deactivation by means of a "Twinned" Disable Device check. After all, a Twinned Greater Sign of Sealing, cast upon one and the same object, may look like only one Greater Sign of Sealing. (The two magic auras may overlap so perfectly that they seem to merge into one, though the Detect Magic spell should still count them as two.) Thus, as a rogue with Disable Device skill, you might go to work disarming this Twinned spell as if it were only one spell – and you might even succeed with exactly the same action as you would need to disarm only one. The only difference would be that at the end of your action (a single action, not a doubled one), you must make two Disable Device checks, and if either one of them fails – ka-BOOM! You get a double explosion.

This third possibility might make sense in this situation and maybe in other ones as well, though I haven't thought through all the consequences, of course. – D. of U.

[Clause]

I see like, if the first desable test fails, this trigger only one explosion. But, if this explosion damages the door, breaking it, so the second explosion occurs