Only the attack's damage would be halved, not the poison damage resulting from a saving throw failure as explained in Sage Advice official ruling ;
Does Uncanny Dodge work automatically against every attack a rogue or ranger gets hit by?Spell attacks too? A use of Uncanny Dodge works against only one attack, since it expends your reaction, and only if you can see the attacker. It works against attacks of all sorts, including spell attacks, but it is no help against a spell or other effect, such as fireball, that delivers its damage after a saving throw rather than after an attack roll.
Uncanny Dodge does not work on anything that has a Saving throw. It does NOT matter that you first had an attack roll. It only works on things that have an attack roll and nothing afterwards.
RAW: Unclear, poorly worded, can be argued either way. Screw it and use RAI.
Why shouldn't we consider the poison damage to be part of the attack? The success/fail contest for the phase spider's bite action depends on a successful attack roll. This action is an attack. There is a saving throw, which serves to adjust the amount of damage inflicted by the attack. I see no distinction in the rules for making an attack, nor for Uncanny Dodge, which segregates certain kinds of damage from others within the attack that caused the damage to be rolled in the first place. The only thing I can find even in the neighborhood of this is a SAC article, which focuses on how many times uncanny dodge can be used and whether it applies to spell attacks--neither of which are relevant to this situation.
Ok, another question about seeing the attacker. The spider was on the ethereal plane, attacked with advantage and it was not being visible until it appeared during the attack. Does the rogue can still use the Uncanny Dodge? He can see it, but only during the attack, not before, he was surprised.
If the attack is rolled with advantage due to being an unseen attacker, then uncanny dodge would not apply. By strict RAW, if a phase spider uses the bonus action to ethereal jaunt into the material plane and then its action to bite, it is no longer unseen. But I think you should absolutely inject some house rule synergy into that situation and roll the bonus action into the action for an unseen attack (which, again, would not let uncanny dodge apply unless the rogue had a way of seeing it coming, such as see invisibility).
I'll also take the stance that the additional poison damage as part of a Phase Spider's bite is the result of the attack itself, and therefore subject to Uncanny Dodge, despite including an additional saving throw to determine the severity of the damage. It is still damage from an attack, just as if being attacked with, say... a Flametongue Weapon, which doesn't include a saving throw but does just add some extra fire damage to attacks.
As for a Phase Spider's Ethereal Jaunt... I see nothing in the creature's stat block that it is considered hidden by teleporting to the ethereal plane. So while the feature does protect the Phase Spider by making it near-impossible to target, it doesn't actually provide it advantage on its next attack when it returns to the material plane, unless it uses its action before returning to Hide... which does introduce a whole mess of logical conundrums that could derail this thread for pages. I think the best way to think of it is that the act of magically teleporting has some kind of obvious element to it... a flash of light, or an audible sound that prevents the Phase Spider from attacking as though it were invisible. Either way, the Phase Spider is visible when it makes the actual attack... even if it was hidden and gained advantage on the attack as a result, the act of attacking removes the Hidden status and makes it visible. Uncanny Dodge works fine in that case; in order to beat Uncanny Dodge the creature attacking needs to be invisible, or heavily obscured, or the Rogue needs to be blinded somehow.
Can the rogue use Uncanny Dodge to halve the poison damage that requires a saving throw? For example, a Phase Spider
Melee Weapon Attack:+4 to hit,, 5 ft., one creature. Hit: 7 (1d10 + 2) piercing damage.
The target must make a DC 11 Constitution saving throw, taking 18 (4d8) poison damage on a failed save, or half as much damage on a successful one.
Can the rogue halve everything? Let's say he succeeded on the saving throw, the damage would be: (1d10+2 + (4d8 / 2)) / 2 ?
Or the poison damage is not halved (again)?
Uncanny Dodge can halve a damage roll if and only if that damage roll can crit, ignoring whether or not that damage roll involves actual dice (i.e. uncanny dodge does work on unarmed attacks and blowpipes). Just as the poison can't crit, it can't be uncannily dodged.
Ok, another question about seeing the attacker. The spider was on the ethereal plane, attacked with advantage and it was not being visible until it appeared during the attack. Does the rogue can still use the Uncanny Dodge? He can see it, but only during the attack, not before, he was surprised.
That's impossible without homebrew, which means we can't answer your question without knowing the exact nature of the homebrew (and bear in mind almost no homebrew is conveyed via a tightly-worded rule we can analyze - usually the DM just has it work how they want it to work). Using non-homebrew RAW, the spider could not attack you from the Ethereal Plane at all, making your question meaningless - the spider would need to enter the Material Plane to attack, which would necessarily mean it was possible to see it when it attacked.
Had the spider instead been invisible and broken that invisibility with the attack, then you would not have been able to use Uncanny Dodge on it, for certain.
Ok, another question about seeing the attacker. The spider was on the ethereal plane, attacked with advantage and it was not being visible until it appeared during the attack. Does the rogue can still use the Uncanny Dodge? He can see it, but only during the attack, not before, he was surprised.
That's impossible without homebrew, which means we can't answer your question without knowing the exact nature of the homebrew (and bear in mind almost no homebrew is conveyed via a tightly-worded rule we can analyze - usually the DM just has it work how they want it to work). Using non-homebrew RAW, the spider could not attack you from the Ethereal Plane at all, making your question meaningless - the spider would need to enter the Material Plane to attack, which would necessarily mean it was possible to see it when it attacked.
Had the spider instead been invisible and broken that invisibility with the attack, then you would not have been able to use Uncanny Dodge on it, for certain.
Uncanny Dodge can halve a damage roll if and only if that damage roll can crit, ignoring whether or not that damage roll involves actual dice.
Your sentence structure looks like you are quoting a rule, but the content of your message feels more like you are making an inference.
It is an inference, and it's one that follows directly from the rules text.
Critical hits let you roll extra dice for "the attack's damage." Uncanny Dodge halves "the attack's damage." If damage dice aren't rolled twice on a crit, they are definitionally not "the attack's damage dice" and do not contribute to "the attack's damage," which means they can't be halved by Uncanny Dodge.
Do you think that a character can use Uncanny Dodge to halve the damage taken when they move after being hit by booming blade? Do you think that damage is rolled twice if the original hit is a crit?
I feel like the booming blade situation is not compatible with uncanny dodge because the secondary damage does not involve an attack made against the target as part of the same action that deals the damage (target movement in this case). I would, however, say that the initial damage from the booming blade attack would include the damage from the weapon attack as well as the thunder damage delivered as part of the attack, assuming the caster was level 5 or higher, and uncanny dodge would cut the combined total damage in half in that case.
In fact, I think booming blade is a good comparison since it combines weapon damage and damage of a different type into a single attack all delivered together similarly to how the phase spider’s bite action does.
In fact, I think booming blade is a good comparison since it combines weapon damage and damage of a different type into a single attack all delivered together similarly to how the phase spider’s bite action does.
I agree that booming blade is a good comparison, since it involves some damage from an attack, plus some separate damage dependent on an additional condition (moving, failed save).
Besides, how would that even work? You use your UD reaction to cut the damage from the attack and then on your turn you use your reaction again when you move? There’s no valid UD trigger after the action containing the attack has ended.
I agree that booming blade is a good comparison, since it involves some damage from an attack, plus some separate damage dependent on an additional condition (moving, failed save).
This isn't exactly accurate, since the poison damage is not separately dependent on an additional condition. The attack inflicts both piercing and poison damage regardless of anything short of immunity. The saving throw only affects how much damage is done. The title of this thread is a bit misleading because there is nothing secondary about the poison damage. It is just integral to the attack as the piercing damage is--in fact, there is no separate process that handles whether or not the poison damage aspect of the attack is inflicted or a mechanism that tacks it on after the fact. A successful attack inflicts piercing damage and poison damage every time, or else it does neither. They are inseparable in terms of Uncanny Dodge.
The poison damage is part of the attack. We know this because if the attack misses, there is no poison damage.
Its part of an effect delivered by the attack but its not part of the attack's damage as it is the result of a saving throw. As others mentioned wether the damage is subject to Crit or not should be a good indicator. A critical hit would double and Uncanny Dodge would halve an attack's damage worded like a green dragon's bite for exemple;
Bite. Melee Weapon Attack: +15 to hit, reach 15 ft., one target. Hit: 19 (2d10 + 8) piercing damage plus 10 (3d6) poison damage.
Only the attack's damage would be halved, not the poison damage resulting from a saving throw failure as explained in Sage Advice official ruling ;
Does Uncanny Dodge work automatically against every attack a rogue or ranger gets hit by?Spell attacks too? A use of Uncanny Dodge works against only one attack, since it expends your reaction, and only if you can see the attacker. It works against attacks of all sorts, including spell attacks, but it is no help against a spell or other effect, such as fireball, that delivers its damage after a saving throw rather than after an attack roll.
Unfortunately this Sage Advice doesn't really answer the question as it tells us nothing about secondary effects.
The fireball example works because a fireball only delivers damage as a result of a saving throw, there is no attack roll involved at any stage of resolving it. However the example in question is indisputably an attack (so Uncanny Dodge definitely applies), the question mark is around what happens to the secondary effect. Way I see it there are two obvious arguments:
A secondary effect is triggered by, but separate from, the attack hitting, i.e- the sequence is resolve attack -> following the hit resolve secondary effect, so it's a separate stage. This is reasonable, but there are no rules that explicitly support this.
The secondary effect is resolved immediately on hit, therefore it is resolved as part of the attack (as opposed to something that happens in a later turn, at the end of the end of the turn etc.). This is also entirely reasonable.
Personally I lean towards the second interpretation because it requires no added steps, whereas the first requires us to create a sequence of timing and separation that the rules never tell us to do, whereas the second option is the simplest, and when it comes to interpreting rules as written often the simplest interpretation is the one that should win (more added steps means less "as written").
In terms of what is the correct interpretation, I think we just don't know, so it's left to the DM (as most weird rules interactions are).
Narratively there are two ways to look at it; either the Rogue dodged so uncannily that they were able to avoid the worst of the poison as well, or they dodged but the poison is so vicious it only required a single drop to deal its damage. Again, either is a reasonable interpretation, which is why it's probably best left to the DM as they can decide how dangerous they want the encounter to be, and how lenient or punishing they want to be to the players.
Can the rogue use Uncanny Dodge to halve the poison damage that requires a saving throw? For example, a Phase Spider
Can the rogue halve everything? Let's say he succeeded on the saving throw, the damage would be: (1d10+2 + (4d8 / 2)) / 2 ?
Or the poison damage is not halved (again)?
If the damage is from the attack, Uncanny Dodge can cut it in half. So yes. All of that damage is cut in half.
"Not all those who wander are lost"
Only the attack's damage would be halved, not the poison damage resulting from a saving throw failure as explained in Sage Advice official ruling ;
The poison damage is part of the attack. We know this because if the attack misses, there is no poison damage.
"Not all those who wander are lost"
That’s a non-sequitur. It’s a consequence of the attack, but it’s a separate effect. It’s not doubled on a crit, and it’s not halved by uncanny dodge.
RAI:
Uncanny Dodge does not work on anything that has a Saving throw. It does NOT matter that you first had an attack roll. It only works on things that have an attack roll and nothing afterwards.
RAW: Unclear, poorly worded, can be argued either way. Screw it and use RAI.
Why shouldn't we consider the poison damage to be part of the attack? The success/fail contest for the phase spider's bite action depends on a successful attack roll. This action is an attack. There is a saving throw, which serves to adjust the amount of damage inflicted by the attack. I see no distinction in the rules for making an attack, nor for Uncanny Dodge, which segregates certain kinds of damage from others within the attack that caused the damage to be rolled in the first place. The only thing I can find even in the neighborhood of this is a SAC article, which focuses on how many times uncanny dodge can be used and whether it applies to spell attacks--neither of which are relevant to this situation.
"Not all those who wander are lost"
Ok, another question about seeing the attacker. The spider was on the ethereal plane, attacked with advantage and it was not being visible until it appeared during the attack. Does the rogue can still use the Uncanny Dodge? He can see it, but only during the attack, not before, he was surprised.
If the attack is rolled with advantage due to being an unseen attacker, then uncanny dodge would not apply. By strict RAW, if a phase spider uses the bonus action to ethereal jaunt into the material plane and then its action to bite, it is no longer unseen. But I think you should absolutely inject some house rule synergy into that situation and roll the bonus action into the action for an unseen attack (which, again, would not let uncanny dodge apply unless the rogue had a way of seeing it coming, such as see invisibility).
"Not all those who wander are lost"
I'll also take the stance that the additional poison damage as part of a Phase Spider's bite is the result of the attack itself, and therefore subject to Uncanny Dodge, despite including an additional saving throw to determine the severity of the damage. It is still damage from an attack, just as if being attacked with, say... a Flametongue Weapon, which doesn't include a saving throw but does just add some extra fire damage to attacks.
As for a Phase Spider's Ethereal Jaunt... I see nothing in the creature's stat block that it is considered hidden by teleporting to the ethereal plane. So while the feature does protect the Phase Spider by making it near-impossible to target, it doesn't actually provide it advantage on its next attack when it returns to the material plane, unless it uses its action before returning to Hide... which does introduce a whole mess of logical conundrums that could derail this thread for pages. I think the best way to think of it is that the act of magically teleporting has some kind of obvious element to it... a flash of light, or an audible sound that prevents the Phase Spider from attacking as though it were invisible. Either way, the Phase Spider is visible when it makes the actual attack... even if it was hidden and gained advantage on the attack as a result, the act of attacking removes the Hidden status and makes it visible. Uncanny Dodge works fine in that case; in order to beat Uncanny Dodge the creature attacking needs to be invisible, or heavily obscured, or the Rogue needs to be blinded somehow.
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Uncanny Dodge can halve a damage roll if and only if that damage roll can crit, ignoring whether or not that damage roll involves actual dice (i.e. uncanny dodge does work on unarmed attacks and blowpipes). Just as the poison can't crit, it can't be uncannily dodged.
That's impossible without homebrew, which means we can't answer your question without knowing the exact nature of the homebrew (and bear in mind almost no homebrew is conveyed via a tightly-worded rule we can analyze - usually the DM just has it work how they want it to work). Using non-homebrew RAW, the spider could not attack you from the Ethereal Plane at all, making your question meaningless - the spider would need to enter the Material Plane to attack, which would necessarily mean it was possible to see it when it attacked.
Had the spider instead been invisible and broken that invisibility with the attack, then you would not have been able to use Uncanny Dodge on it, for certain.
That's impossible without homebrew, which means we can't answer your question without knowing the exact nature of the homebrew (and bear in mind almost no homebrew is conveyed via a tightly-worded rule we can analyze - usually the DM just has it work how they want it to work). Using non-homebrew RAW, the spider could not attack you from the Ethereal Plane at all, making your question meaningless - the spider would need to enter the Material Plane to attack, which would necessarily mean it was possible to see it when it attacked.
Had the spider instead been invisible and broken that invisibility with the attack, then you would not have been able to use Uncanny Dodge on it, for certain.
Your sentence structure looks like you are quoting a rule, but the content of your message feels more like you are making an inference.
"Not all those who wander are lost"
It is an inference, and it's one that follows directly from the rules text.
Critical hits let you roll extra dice for "the attack's damage." Uncanny Dodge halves "the attack's damage." If damage dice aren't rolled twice on a crit, they are definitionally not "the attack's damage dice" and do not contribute to "the attack's damage," which means they can't be halved by Uncanny Dodge.
Do you think that a character can use Uncanny Dodge to halve the damage taken when they move after being hit by booming blade? Do you think that damage is rolled twice if the original hit is a crit?
I feel like the booming blade situation is not compatible with uncanny dodge because the secondary damage does not involve an attack made against the target as part of the same action that deals the damage (target movement in this case). I would, however, say that the initial damage from the booming blade attack would include the damage from the weapon attack as well as the thunder damage delivered as part of the attack, assuming the caster was level 5 or higher, and uncanny dodge would cut the combined total damage in half in that case.
In fact, I think booming blade is a good comparison since it combines weapon damage and damage of a different type into a single attack all delivered together similarly to how the phase spider’s bite action does.
"Not all those who wander are lost"
I agree that booming blade is a good comparison, since it involves some damage from an attack, plus some separate damage dependent on an additional condition (moving, failed save).
Besides, how would that even work? You use your UD reaction to cut the damage from the attack and then on your turn you use your reaction again when you move? There’s no valid UD trigger after the action containing the attack has ended.
This isn't exactly accurate, since the poison damage is not separately dependent on an additional condition. The attack inflicts both piercing and poison damage regardless of anything short of immunity. The saving throw only affects how much damage is done. The title of this thread is a bit misleading because there is nothing secondary about the poison damage. It is just integral to the attack as the piercing damage is--in fact, there is no separate process that handles whether or not the poison damage aspect of the attack is inflicted or a mechanism that tacks it on after the fact. A successful attack inflicts piercing damage and poison damage every time, or else it does neither. They are inseparable in terms of Uncanny Dodge.
"Not all those who wander are lost"
Its part of an effect delivered by the attack but its not part of the attack's damage as it is the result of a saving throw. As others mentioned wether the damage is subject to Crit or not should be a good indicator. A critical hit would double and Uncanny Dodge would halve an attack's damage worded like a green dragon's bite for exemple;
Unfortunately this Sage Advice doesn't really answer the question as it tells us nothing about secondary effects.
The fireball example works because a fireball only delivers damage as a result of a saving throw, there is no attack roll involved at any stage of resolving it. However the example in question is indisputably an attack (so Uncanny Dodge definitely applies), the question mark is around what happens to the secondary effect. Way I see it there are two obvious arguments:
Personally I lean towards the second interpretation because it requires no added steps, whereas the first requires us to create a sequence of timing and separation that the rules never tell us to do, whereas the second option is the simplest, and when it comes to interpreting rules as written often the simplest interpretation is the one that should win (more added steps means less "as written").
In terms of what is the correct interpretation, I think we just don't know, so it's left to the DM (as most weird rules interactions are).
Narratively there are two ways to look at it; either the Rogue dodged so uncannily that they were able to avoid the worst of the poison as well, or they dodged but the poison is so vicious it only required a single drop to deal its damage. Again, either is a reasonable interpretation, which is why it's probably best left to the DM as they can decide how dangerous they want the encounter to be, and how lenient or punishing they want to be to the players.
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