Otiluke's Resilient Sphere of Drowning Implosion

[Saintheart]

CL 7 Otiluke's Resilient Sphere produces a sphere 7 feet in diameter centred around some unfortunate hobgoblin. This has a volume of 1,300 gallons or so.

Dark Tide (Stormwrack, p. 115) is a Necromancy spell, and causes blackwater to emanate from a given point of origin at 100 feet per round "until it fills the entire area". Therefore the point of origin can be within the Sphere. The Sphere's not a creature, and Dark Tide is not a Conjuration spell anyway - and thus is not bound to the stricture that says Conjuration spells can't conjure something inside a creature. Nothing can pass through the Sphere's walls - in or out - but we aren't making anything go through it anyway, we're setting a spell to fire off within it. If we had a lot of wands of Create Water and a lot of patience we could do much the same thing since the Sphere lasts min/level.

Anyway, in about a round or two the creature is either drowning or has imploded under the weight of water pouring into the Sphere's unbreakable space. Bonus points, assuming the water can continue to fill the space so a half mile's worth of water is within a 7 foot sphere, the resulting explosion of water when the Sphere's spell duration ends should be pretty spectacular.

Doubtless I've missed something, but can someone kindly tell me what?

[Kurald Galain]

I'm not sure why you would assume the creature implodes; if the sphere fills with water, the creature simply has to follow the swimming rules. That does mean he'll likely drown, yes.

However, you don't have line of effect to the inside of the sphere, therefore you cannot target spells there. By the magic rules (https://www.d20srd.org/srd/magicOverview/spellDescriptions.htm), "You must have a clear line of effect to the point of origin of any spell you cast."

[Kitsuneymg]

Even if you cast the water spell first and then trapped it in a sphere, it says it stops when the volume is filled. Why would you assume it continues to pump water into the sphere creating pressure when it says the opposite?

[Saintheart]

I'm not sure why you would assume the creature implodes; if the sphere fills with water, the creature simply has to follow the swimming rules. That does mean he'll likely drown, yes.

However, you don't have line of effect to the inside of the sphere, therefore you cannot target spells there. By the magic rules (https://www.d20srd.org/srd/magicOverview/spellDescriptions.htm), "You must have a clear line of effect to the point of origin of any spell you cast."

(1) Implosion - sure, but it depends what "fills the area" means. The area the spell fills is about half a mile radius. So either the spell automatically stops when it realises it can't fill anything more, or it mindlessly keeps producing water into a sphere area that is indestructible, creating higher and higher pressure within the sphere.

(2) Line of effect is probably right, but line of sight doesn't block line of effect. A solid barrier does. But the subject of Resilient Sphere can breathe normally, so it arguably isn't the "solid barrier" that blocks line of effect for the purposes of magic. Nothing can pass in or out, but we're not flinging a fireball at the centre of the sphere.


Even if you cast the water spell first and then trapped it in a sphere, it says it stops when the volume is filled. Why would you assume it continues to pump water into the sphere creating pressure when it says the opposite?

(3) See above; it says it stops when the area is filled. The area the spell affects is a half mile radius. So either it stops at the sphere's boundary, or it continues to mindlessly pour water into a sphere which can't be broken.

[Kurald Galain]

But the subject of Resilient Sphere can breathe normally
More likely, that means that the sphere is big enough that the air inside is just not going to run out during the duration of the spell.

I'd find it pretty weird to think that an impassible globe of force is somehow not solid or not a barrier.

[sleepyphoenixx]

I'd find it pretty weird to think that an impassible globe of force is somehow not solid or not a barrier.
I agree. If nothing gets in or out that includes magic. A specific exception (the subject can breathe normally) doesn't mean there's an exception for anything else.

Even aside from that getting your DM to agree that Resilient Sphere doesn't block LoE is shooting yourself in the foot. You want it to block LoE, it's much more useful that way.

[Kurald Galain]

(2) Line of effect is probably right, but line of sight doesn't block line of effect. A solid barrier does. But the subject of Resilient Sphere can breathe normally, so it arguably isn't the "solid barrier" that blocks line of effect for the purposes of magic.
It strikes me that if you follow this line of reasoning, then your combo doesn't work because Resilient Sphere spells out that the subject can breathe normally. Therefore he cannot drown. :smallamused:

[Elves]

His point isn’t that they would drown but that they would die of pressure. Let’s remove the resilient sphere and just assume you cast dark tide in a sealed 10x10 room.

The until area is filled rules lawyering is clever and plausible. The fact that it goes beyond published rules into real world physics makes the other ruling more in line with RAW IMO but I can see an open minded DM accepting it. Keep in mind though that with a half-mile radius the water pressure thing would apply in many closed spaces.

[cython]

Will an "Invisible Spell" Otiluke's Resilient Sphere will solve the issue of line of effect?

A

[KillianHawkeye]

Will an "Invisible Spell" Otiluke's Resilient Sphere will solve the issue of line of effect?

No, that will just make it a globe of invisible force rather than a globe of shimmering force.

Line of sight and line of effect are completely different things.

[Metastachydium]

It strikes me that if you follow this line of reasoning, then your combo doesn't work because Resilient Sphere spells out that the subject can breathe normally. Therefore he cannot drown. :smallamused:


His point isn’t that they would drown but that they would die of pressure. Let’s remove the resilient sphere and just assume you cast dark tide in a sealed 10x10 room.

The until area is filled rules lawyering is clever and plausible. The fact that it goes beyond published rules into real world physics makes the other ruling more in line with RAW IMO but I can see an open minded DM accepting it. Keep in mind though that with a half-mile radius the water pressure thing would apply in many closed spaces.

I'm starting to think hobgoblins are a suboptimal choice as victims to use. Hear me out:

Aventi: [all smug] Foolish dirt-dweller! I breathe within water as your ilk breathes without!
Crazy Caster Person: [smirks] Do you, now? Do you?
[Aventi goes SPLRTKCHCH.]

[spectralphoenix]

TBH, Dark Tide is just poorly written. It gives an area, but not a volume or a height, so there's no way of knowing how much water is actually created, how hard it is to avoid, whether you can swim or drown in it, and so on. It should also probably be a conjuration spell*. As it is, I think the reasonable interpretation is that it summons a few inches of water across the area, and the whole area is a few inches deep regardless of topography or containment. Anything else would probably do so much damage by sweeping away and drowning creatures or washing out structures that the strength damage would be an afterthought. That said, it's vague enough a DM could rule anything.


*The conjuration rules prevent you from creating things inside another object, so presumably once a container was full you couldn't bring in anymore water to increase the pressure.

[Kitsuneymg]

His point isn’t that they would drown but that they would die of pressure. Let’s remove the resilient sphere and just assume you cast dark tide in a sealed 10x10 room.

The until area is filled rules lawyering is clever and plausible. The fact that it goes beyond published rules into real world physics makes the other ruling more in line with RAW IMO but I can see an open minded DM accepting it. Keep in mind though that with a half-mile radius the water pressure thing would apply in many closed spaces.

It’s a half mile spread area. Use the spread rules. When the area the spell can go (around corners etc) is filled, you’re done. You don’t get double damage on a fireball if a pillar lets two “edges” wrap around to the same square. It doesn’t backblast if launched into a shallow alcove either. It fills the area, then stops. The only difference is that this gives a rate it fills at instead of being instantaneous like normal spreads.

> based on real world physics
> in 3.x

I want whatever you’re smoking.

[Elves]

I mean look, if the water literally continues until it fills a half-mile radial spread it would continue until the worlds water level had risen to a half mile above your position.
that seems to debunk the method here.

[Elenian]

Spell to Power Erudite with burrowing power, maybe, if you really must cast into an already-existing resilient sphere?

Dark Tide is a super weird spell. It has a wildly nonlinear rate of blackwater production, a spread radius rather than any kind of volume figures, and lord knows what happens if you cast it at a point in midair (blackwater rain over an increasingly large area, I suppose?)


Bonus points, assuming the water can continue to fill the space so a half mile's worth of water is within a 7 foot sphere, the resulting explosion of water when the Sphere's spell duration ends should be pretty spectacular.


Assuming your DM were mad enough to play this by real-world physics, the explosion wouldn't contain any 'water' anymore. A half-mile radius sphere has a volume of around 2*10^9 cubic meters. A 7 foot sphere has a volume of around 40 cubic meters. So we're compressing our water by, um, 99.999998%. The bulk modulus of water at room temperature is about 2x10^9 Nm^-2 (our water is most definitely not going to stay at room temperature, but as we'll see the numbers are titanic enough that this simplification doesn't really matter). Quick math shows that our water is going to be under something like 10^17Pa of pressure, or... about four times the pressure at the core of the sun. So, yeah, we're well into 'fusion plasma' territory here.

[SpyOne]

1) The pressure of the water in the sphere is going to be limited to the pressure it is being delivered at. When you reach the same pressure as the source, water stops going in. Unless Dark Tide creates water with a high enough pressure that it can be used as a blunt force attack, the pressure inside the sphere probably isn't going to get very high.

2) Water is very hard to compress. That's why hydraulics work. You need to get up to a lot of pressure before the density of water is noticeably affected. So even at really high pressure, when the sphere spell ends and the pressure returns to normal you'll have around 1300 gallons.

I think drowning trapped creatures is sufficiently gruesome and effective with out resorting to hyperbole.

[Beni-Kujaku]

Honestly‚ a tide is not water. It's the movement of water. I don't know if you can cast the spell when there's not enough water nearby (hence the fact that it isn't Conjuration‚ contrary to Create Water)