Damage overflow and resistance/ vulnerability

[No brains]

Nobody can think up a RAW answer to this, so it's time to jump into the ocean of conjecture. What does everyone think about this quandry?


Q362 When a creature takes 'overflow' damage that breaks Wildhsape or Polymorph, how do immunities, resistances, and vulnerabilities work?

Example A: A salamander is polymorphed into crab and hit with fireball for 30 damage. Is the salamander immune to the overflow damage?

Example B: A commoner is polymorphed into a skeleton* and takes 30 bludgeoning damage. Is the overflow damage still doubled by the skeleton's vulnerability to bludgeoning damage?

*I know polymorph can't turn a creature into a skeleton, I was just reaching for some creature that had a vulnerability.

Q363 Are there any beasts that have a damage vulnerability?

[moonfly7]

If say the answer is this: you take only the damage prescribed by your form. If ypur other form is weak to bludgeoning, when you get the remain damage, you only take the normal amount left. But if your immune to fire, or even resistant, I think it carries between forms, especially if it's a class feature. Correct me if I'm wrong, but at least with wildshape, I'm pretty sure your resistances and stuff carry to other forms.

[dickerson76]

"Example A: A salamander is polymorphed into crab and hit with fireball for 30 damage. Is the salamander immune to the overflow damage?
Yes. Crab takes 30 fire damage. It is reduced to 0 hp after 1 point of damage (I'm not sure on crab stats, so I'm making that up for the sake of the example). Crab turns back into a salamander. Salamander takes 29 points of fire damage (reduced to 0 due to immunity). There are no rules written to say that it would happen any other way, so RAW seems clear to me. The damage doesn't stop being fire damage just because it rolled over.


Example B: A commoner is polymorphed into a skeleton* and takes 30 bludgeoning damage. Is the overflow damage still doubled by the skeleton's vulnerability to bludgeoning damage?"
I'm not sure on skeleton stats, so: Assume skeleton has 10 HP remaining. Skeleton takes 30 bludgeoning damage. The first 5 of that (doubled to 10 due to vulnerability) reduces skeleton form to 0. 25 damage rolls over to commoner form. If it the damage source had two types (something like a spell that does X fire and Y bludgeoning damage), I'd apply them to the skeleton form if whatever way is most advantageous for the players (ie, fire first is the commoner/skeleton is an ally; bludgeoning first if the commoner/skeleton is an enemy).

[ThePolarBear]

Nobody can think up a RAW answer to this, so it's time to jump into the ocean of conjecture. What does everyone think about this quandry?

You could apply the same ruling for resistances and arcane ward (https://twitter.com/JeremyECrawford/status/525030313571790848). Or something else. In theory, you should not apply resistances twice to the same damage type. But that's the extent of the guidelines.

If using the above:
Vuln -> normal or Vuln: all damage that passes.
Vuln -> Res : halve the damage that passes.
Res -> normal or Res: all damage that passes.
Res -> Vuln : Double the damage.
Imm -> whatever : nope.
whatever -> Imm : still nope.

If you consider the damage a "new" source, then apply resistances again, too.

[Keravath]

My opinion is that resistances and vulnerabilities only apply to the form with those resistances and vulnerabilities.

Enough damage is applied to reduce the current shape to zero hit points (doubled, halved or normal depending on the vulnerabilities or resistances of the form. Any remaining damage is applied to the base form after the polymorph or wild shape ends. Remaining damage is applied without changing damage type and applying the resistances and vulnerabilities of the new form to the damage.

So a polymorphed yuan-ti pureblood takes 40 poison damage. 30 damage is sufficient to end the polymorph, 10 poison damage is applied to the base form which is immune to poison so no additional damage is taken.

An elemental true polymorhped into a skeleton takes 30 bludgeoning damage. The skeleton has 20 hit points left but is vulnerable to bludgeoning so only 10 bludgeoning damage is required to reduce the skeleton to zero. This leaves 20 bludgeoning damage to be applied to the base form. The elemental is resistant to non-magical bludgeoning damage so the remaining 20 damage does 10 hit points of damage to the elemental.

Although, these examples aren't explicitly spelled out in RAW, the different creature damage vulnerabilities and resistances are. In addition, these do not carry over between forms unless explicitly mentioned. As a result, I think the interpretation above is consistent with RAW, since anything else has to assume that the resistances and immunities carry over between forms. 30 damage is still 30 damage, it just causes 15 points of hit point damage taken if a creature is resistant and 60 if a creature is vulnerable.


(In the case of wild shape, resistances and immunities explicitly carry over from the base form e.g. a yuan-ti pureblood druid wild-shaped to a bear is still immune to poison).

"You retain the benefit of any features from your class, race, or other source and can use them if the new form is physically capable of doing so. However, you can't use any of your special senses, such as darkvision, unless your new form also has that sense."

Class and race features include resistances and immunities.

[Grey Watcher]

The tables I've played at have generally ruled (as would I if the situation came up on my watch) that it goes like this:


Calculate damage based on target's current form's resistances, vulnerabilities and immunities
Apply damage
If polymorph is ended by damage, apply remainingdamage without further modification


As you say, RAW could go either way, but we've found that this is a handy compromise between 3E''s "polymorph to bug, killing bug, circumvent entire combat" and "polymorph is too fragile to be useful in a combat situation". Plus it gives tactics like the Onion Druid a potential downside, in the form of (potentially) giving up important vulnerabilities. (citation needed)

All that said, I can still appreciate the logic of the other reading.