# Thread: Dust of Dryness Goes Nuclear

1. ## Dust of Dryness Goes Nuclear

Dust of Dryness. It's cute. It's amusing. It's a nice way to carry around lots of water for a desert campaign and the like.

Then one of my players turned it into one of the most lethal (albeit very specific) weapons in D&D.

How did this happen? Well, we start with the description of Dust of Dryness: "This small packet contains 1d6 + 4 pinches of dust. You can use an action to sprinkle a pinch of it over water. The dust turns a cube of water 15 feet on a side into one marble-sized pellet, which floats or rests near where the dust was sprinkled. The pellet's weight is negligible." So lets do some math on that.
1. A cube that is 15 feet on one side is 15 x 15 x 15 = 3375 cubic feet of water.
2. There are 7.48052 gallons in a cubic foot of water.
3. So the tiny marble you used to capture water contains 25,246.755 gallons of water.

Now we look at Fire Elementals: "Water Susceptibility. For every 5 ft. the elemental moves in water, or for every gallon of water splashed on it, it takes 1 cold damage."

So one of my players stows away two pellets full of water from the Dust of Dryness, and we proceed with our Desert Campaign. So when they run into a group of Fire Elementals, the only question was: How do I drop the water on as many of them as possible??

25,247 damage is an insane amount of damage. Like being blasted so hard that you weren't actually born.

2. ## Re: Dust of Dryness Goes Nuclear

The Mod on the Silver Mountain: Moved to Roleplaying Games.
Originally Posted by GodofThunder555
Dust of Dryness. It's cute. It's amusing. It's a nice way to carry around lots of water for a desert campaign and the like.

Then one of my players turned it into one of the most lethal (albeit very specific) weapons in D&D.

How did this happen? Well, we start with the description of Dust of Dryness: "This small packet contains 1d6 + 4 pinches of dust. You can use an action to sprinkle a pinch of it over water. The dust turns a cube of water 15 feet on a side into one marble-sized pellet, which floats or rests near where the dust was sprinkled. The pellet's weight is negligible." So lets do some math on that.
1. A cube that is 15 feet on one side is 15 x 15 x 15 = 3375 cubic feet of water.
2. There are 7.48052 gallons in a cubic foot of water.
3. So the tiny marble you used to capture water contains 25,246.755 gallons of water.

Now we look at Fire Elementals: "Water Susceptibility. For every 5 ft. the elemental moves in water, or for every gallon of water splashed on it, it takes 1 cold damage."

So one of my players stows away two pellets full of water from the Dust of Dryness, and we proceed with our Desert Campaign. So when they run into a group of Fire Elementals, the only question was: How do I drop the water on as many of them as possible??

25,247 damage is an insane amount of damage. Like being blasted so hard that you weren't actually born.
But you're not splashing 25,000 gallons on them. Not unless the Fire Elemental is Huge - there's a lot of water that's being dumped near them but not on them. Now, granted, it's still almost definitely enough to kill a Fire Elemental, but it's not 25,247 damage, strictly speaking.

3. ## Re: Dust of Dryness Goes Nuclear

Originally Posted by Peelee
The Mod on the Silver Mountain: Moved to Roleplaying Games.

But you're not splashing 25,000 gallons on them. Not unless the Fire Elemental is Huge - there's a lot of water that's being dumped near them but not on them. Now, granted, it's still almost definitely enough to kill a Fire Elemental, but it's not 25,247 damage, strictly speaking.
They flew over a line of them, so gravity kinda took care of that. One of those fun desert "flames shoot up out of the ground, followed by fire elementals" kinds of things -- so the elementals came out packed together. And yeah, not all of it hit's its target, but a whole lot can miss the target while remaining more than lethal enough to kill them.

Just one of those times when a seemingly useless item became insanely useful. I was highly amused.

I do kind of get the feeling that this was an oversight by the writers. A fire elemental can walk through water -- lots of it -- and only takes 1 point of damage per 5 feet. But if you can throw water on them, totally different story. It gave me a chuckle so I had no problem allowing it without modification.

4. ## Re: Dust of Dryness Goes Nuclear

Originally Posted by GodofThunder555
They flew over a line of them, so gravity kinda took care of that. One of those fun desert "flames shoot up out of the ground, followed by fire elementals" kinds of things -- so the elementals came out packed together. And yeah, not all of it hit's its target, but a whole lot can miss the target while remaining more than lethal enough to kill them.

Just one of those times when a seemingly useless item became insanely useful. I was highly amused.

I do kind of get the feeling that this was an oversight by the writers. A fire elemental can walk through water -- lots of it -- and only takes 1 point of damage per 5 feet. But if you can throw water on them, totally different story. It gave me a chuckle so I had no problem allowing it without modification.
The downside of this is of course that they've used up a vast amount of water resources that they could otherwise have been drinking in their desert adventure.
Sure, there are other ways of getting water, but that's using up resources again.

5. ## Re: Dust of Dryness Goes Nuclear

Originally Posted by Altair_the_Vexed
The downside of this is of course that they've used up a vast amount of water resources that they could otherwise have been drinking in their desert adventure.
Sure, there are other ways of getting water, but that's using up resources again.
Unless it's Dark Sun or something conceptually similar (and party is lvl 3+) I doubt there is a lot of danger of dying from thirst for a prepared party - there's always rings of sustenance, hydration suit, spells and special abilities galore, something which renders the party entirely or close to self-sufficient.

And those pellets are less impressive than they look for water needs. You cannot carry all that water, so a pellet is "refill all your containers, once" and not "supply a party of six for two years or more". A desert fort with a well-isolated underground cistern may be able to get the full benefit of a pellet, travelers - not so much.

6. ## Re: Dust of Dryness Goes Nuclear

Originally Posted by Altair_the_Vexed
The downside of this is of course that they've used up a vast amount of water resources that they could otherwise have been drinking in their desert adventure.
Sure, there are other ways of getting water, but that's using up resources again.
It's the Calim Desert in Forgotten Realms, but with the efreeti Memnon and the djinn Calim still imprisoned (so pre-Spellplague). They're high enough level that they'll likely be okay. Plus, they managed to make something useful out of something I threw out as a joke: The Thimble of Holding. Ends up only really being useful for carrying 1 cubic foot of water and you need a 1.5 foot long metal straw to even get to the water, but they're doing good for water at this point since several are carrying around 7.5 gallons of it. What can I say? I've got an innovative bunch and I just have to be more careful about making up magical items that I think are completely useless. The Thimble of Holding holds 1 cubic foot of material. As for gravity for the items inside the pocket dimension, down is always pointed towards the bottom of the thimble, so turning it upside down will not dump out any of the contents. I sure didn't make it easy for them!

The player in question was the only one who wanted the Dust of Dryness when it came up in the randomly generated loot from a monster lair. I think she was thinking of something like this all along, since she already had the Thimble of Holding full of water. It was a fun and amusing surprise to see what she was able to do when combining Dust of Dryness with a Broom of Flying. I'm certainly not going to be one to punish thoughtful and creative innovation -- but unfortunately, Fire Elementals aren't the only one with Water Vulnerability reading exactly the same way: 1 gallon = 1 point of damage.

I guess the price on Dust of Dryness should be astronomical in Calimport and other Calimshan cities.

7. ## Re: Dust of Dryness Goes Nuclear

See I thought you meant nuclear as in "trigger sufficient pellets at once in a confined space for the pressure to cause nuclear fusion". I'm not sure how many it would take, but given that it's compressing a 15' cube of water into a marble-sized pellet, it seems like it would be possible.

The containment vessel would need to be something indestructible like Riverrine.

8. ## Re: Dust of Dryness Goes Nuclear

Yeah, most players when given Dust of Dryness will use it in an offensive way. Dropping it on fire elementals is a good idea, the most common use I've seen is "drown an enemy trapped in a confined space".

9. ## Re: Dust of Dryness Goes Nuclear

Originally Posted by icefractal
See I thought you meant nuclear as in "trigger sufficient pellets at once in a confined space for the pressure to cause nuclear fusion". I'm not sure how many it would take, but given that it's compressing a 15' cube of water into a marble-sized pellet, it seems like it would be possible.

The containment vessel would need to be something indestructible like Riverrine.
Liquids don't compress naturally, so it should probably already be capable of nuclear fusion.

10. ## Re: Dust of Dryness Goes Nuclear

Danger! Do not swallow!

Or, "What happens if I throw the pellet down the dragons throat?"

11. ## Re: Dust of Dryness Goes Nuclear

Originally Posted by WanderingMist
Liquids don't compress naturally, so it should probably already be capable of nuclear fusion.
Well, you could rule that rather than being compressed the Dust is actually storing the water somewhere else as if it were an extremely specialized bag of holding/portable hole.

12. ## Re: Dust of Dryness Goes Nuclear

Well....
Liquids can compress...just things are a mite different.
Kinda like how the 35.5+ kg of plutonium will be compressed to size of walnut...just very briefly...that's what the explosives are for....

But as for the water I figure the idea is that the when the dust returns to water to a space too small to fit it...because the magic of the dust made marble can not be compression because that would mean a conservation of mass....and go ahead please try to pick up a 15ft cube of water...let a alone throw....I'll wait.
So yeah...the marble is a marker for some kind of specialized rope trick style effect IMO.

13. ## Re: Dust of Dryness Goes Nuclear

Originally Posted by icefractal
See I thought you meant nuclear as in "trigger sufficient pellets at once in a confined space for the pressure to cause nuclear fusion". I'm not sure how many it would take, but given that it's compressing a 15' cube of water into a marble-sized pellet, it seems like it would be possible.

The containment vessel would need to be something indestructible like Riverrine.
We're endangering catgirls with how much we're trying to apply real world physics to D&D magic at this point.

It *might* be that the Drying Dust pellet fails to release its hold if it is submerged in a space already full of water.

As a DM, if my players wanted to play with these ideas in my game, I'd allow for them to create a hydraulic bomb of sorts, but it's probably going to wind up being roughly equivalent in power to a bog standard Fireball spell that deals bludgeoning damage instead of fire damage.

I'm not going to let them jury-rig any kind of fission or fusion into the game. Characters that try are just going to continue to fail to get it to work. Characters that persist at the expense of the plot will be given mandatory retirement from the game and the player asked to pick another character that is going to pursue the adventure while their original character spends the rest of their lives pursuing the secrets of the atom.

14. ## Re: Dust of Dryness Goes Nuclear

Originally Posted by Pleh
We're endangering catgirls with how much we're trying to apply real world physics to D&D magic at this point....
What about using the dust as a propellant in something like a mortar or artillery? All that water being released in a tube at once would create a lot of force. The pellets would be much safer for ships to carry than gunpowder.

15. ## Re: Dust of Dryness Goes Nuclear

Originally Posted by Vizzerdrix
What about using the dust as a propellant in something like a mortar or artillery? All that water being released in a tube at once would create a lot of force. The pellets would be much safer for ships to carry than gunpowder.
A crate, full of pellets, all of which react explosively when wet.... On a vessel at sea.

And this is supposed to be safer for ships than gunpowder?

16. ## Re: Dust of Dryness Goes Nuclear

While obviously I wouldn’t recommend playing D&D in general, if you have to it is a good idea to make it clear that any attempts at physics will cut both ways.

Feathers, for instance, have reasonably high terminal velocity when falling. If you went from 0 m/s to 3 m/s so fast that it made no difference and allowed you to travel at maximum flight spell speed the same round, we can only assume you accelerated at roughly 1000 kph^2 and are now dead. If light completely bent around you to make you invisible, then by definition it isn’t reaching your eyes, so you are now blind. If you dodged a lightning bolt with a reflex save, you literally moved faster than light and are now dead.

And so forth.

Or everyone can admit that D&D isn’t the place for physics.

17. ## Re: Dust of Dryness Goes Nuclear

I prefer to make it clear that while the outward appearance is pretty Earth-like, the actual underpinnings are very different. Basically, the physical laws are more like "what if medieval alchemists were mostly right?" Everything they could directly observe/understand works right how they'd expect it to. But anything requiring even 17th century knowledge and tools? Hah. No.

There are no atoms. No molecules. No conservation laws. No photosynthesis. Light is not a particle or a wave. In fact, there is such a thing as darkness, not just the absence of light. All those cycles so necessary for life? They're under the direct supervision of the elementals, that being their role in the planar economy.

At the level you can interact with it as a character without beaching the 4th wall, everything is normal. Try to metagame your half remembered physics classes into the game and it won't work out well.

Side note, I have a phd in quantum chemistry and taught both physics and chemistry class at high school and university level. So yeah. I don't want to have to hear you butcher things. Nor do I want to kill cat girls.

18. ## Re: Dust of Dryness Goes Nuclear

Originally Posted by GodofThunder555
They flew over a line of them, so gravity kinda took care of that. One of those fun desert "flames shoot up out of the ground, followed by fire elementals" kinds of things -- so the elementals came out packed together. And yeah, not all of it hit's its target, but a whole lot can miss the target while remaining more than lethal enough to kill them.
I mean, if you're flying over them you could just drop whatever. That's called a lazy dog projectile and even before its historical use it had already been described in part 3 of Gulliver's Travels

Originally Posted by PhoenixPhyre
I prefer to make it clear that while the outward appearance is pretty Earth-like, the actual underpinnings are very different. Basically, the physical laws are more like "what if medieval alchemists were mostly right?" Everything they could directly observe/understand works right how they'd expect it to. But anything requiring even 17th century knowledge and tools? Hah. No.

There are no atoms. No molecules. No conservation laws. No photosynthesis. Light is not a particle or a wave. In fact, there is such a thing as darkness, not just the absence of light. All those cycles so necessary for life? They're under the direct supervision of the elementals, that being their role in the planar economy.

At the level you can interact with it as a character without beaching the 4th wall, everything is normal. Try to metagame your half remembered physics classes into the game and it won't work out well.

Side note, I have a phd in quantum chemistry and taught both physics and chemistry class at high school and university level. So yeah. I don't want to have to hear you butcher things. Nor do I want to kill cat girls.
It must reduce to real world physics under most day to day conditions - including a lot of chemical reactions that we don't ordinarily think about - in order to have anything human enough to be reasonably considered "human". Our bodies are evolved to take advantage of real world chemistry. Change chemistry, and you radically change the internal organs, as well as animals, plants, everything.

19. ## Re: Dust of Dryness Goes Nuclear

Originally Posted by Bohandas
It must reduce to real world physics under most day to day conditions - including a lot of chemical reactions that we don't ordinarily think about - in order to have anything human enough to be reasonably considered "human". Our bodies are evolved to take advantage of real world chemistry. Change chemistry, and you radically change the internal organs, as well as animals, plants, everything.
Yes, and? How do you measure that without microscopes and the rest of modern science (modern as in post 1400 or so)? Cut someone open and they have blood, hearts, etc. Internally, those don't function the same way. No cells, dna, biochemistry, etc. But at the surface, it looks and acts/has the same gross functionality as a 1200's alchemist would expect.

20. ## Re: Dust of Dryness Goes Nuclear

I mean that the entire viscera would have to be different, not just that the organs would have to operate differently at a microscopic level. In particular the liver, the kidneys, (and the tissues in the stomach and intestines that excrete digestive juices), just do chemistry

21. ## Re: Dust of Dryness Goes Nuclear

Originally Posted by Bohandas
I mean that the entire viscera would have to be different, not just that the organs would have to operate differently at a microscopic level. In particular the liver, the kidneys, (and the tissues in the stomach and intestines that excrete digestive juices), just do chemistry
In earth humans. They still perform the same functions in my setting, but the way they do so is very different.

And remember, think like a 13th century alchemist. You know there are viscera, but you have no clue what they do, and all the ideas you do have are...well... Not exactly so by modern standards. Only that cutting them out is bad. You know nothing of biochemistry, or what we call chemistry. Here, the humors theory is, if not entirely true, much more true than on earth. Just adjusted so that said alchemist couldn't tell the difference.

22. ## Re: Dust of Dryness Goes Nuclear

Originally Posted by Bohandas
I mean, if you're flying over them you could just drop whatever. That's called a lazy dog projectile and even before its historical use it had already been described in part 3 of Gulliver's Travels
I wager it would work against more than just fire elementals, too. Having 25,000 gallons — or about 94 metric tons — of water dropped on top of your head seems unhealthy, fire elemental or not.
Could make an excellent siege weapon as well. Launch a couple of these at an enemy keep and you've got a very efficient way to clear the walls for an assault (and possibly flood the whole place while you're at it). Or just have your bird familiar drop it on them, should you prefer a surprise attack.

23. ## Re: Dust of Dryness Goes Nuclear

Originally Posted by BlueScreen85
I wager it would work against more than just fire elementals, too. Having 25,000 gallons — or about 94 metric tons — of water dropped on top of your head seems unhealthy, fire elemental or not.
Yes, but far far more expensive than dropping rocks

24. ## Re: Dust of Dryness Goes Nuclear

Originally Posted by Bohandas
Yes, but far far more expensive than dropping rocks
Sure, but far superior logistically as well. In order to drop rocks you have to actually lift those rocks up to a height, not to mention carry a bunch of big, heavy rocks around. You could have several of these in your pocket, and just stick one at the tip of an arrow, or have a flying familiar/player drop it from above.

It won't beat a trebuchet volley in raw destructive efficiency, but it's an incredibly effective weapon and doesn't need a crew to move, set up and operate.

25. ## Re: Dust of Dryness Goes Nuclear

I think I can improve on this. What if we stuck it in a chamber in the center of a container made out of several layers of flaky metal, thus creating a fragmentation grenade effect in addition to the deluge. If the DM rules that the water can only reappear in a space big enough to hold it, the addition of a tesla valve will restore functionality EDIT: On second thought, a simple pinhole will probably work as well as a tesla valve. The important thing is that the water is able to escape but not to escape fast enough to avoid bursting the container.

26. ## Re: Dust of Dryness Goes Nuclear

Originally Posted by Bohandas
If the DM rules that the water can only reappear in a space big enough to hold it, the addition of a tesla valve will restore functionality EDIT: On second thought, a simple pinhole will probably work as well as a tesla valve. The important thing is that the water is able to escape but not to escape fast enough to avoid bursting the container.
I don't see why this would work. Poking a hole in the container doesn't change how much space there is inside it, which is the actual bar to the water reappearing.

27. ## Re: Dust of Dryness Goes Nuclear

The container is no longer a closed space

28. ## Re: Dust of Dryness Goes Nuclear

Originally Posted by Bohandas
The container is no longer a closed space
True, but irrelevant. You proposed a situation where the DM ruled that "the water can only reappear in a space big enough to hold it". Putting a hole in the side of a container doesn't change the container's volume, and thus doesn't change whether or not the water can appear inside the container.

29. ## Re: Dust of Dryness Goes Nuclear

Originally Posted by Bohandas
The container is no longer a closed space
The water appears in and around the container. You now have a metal ball inside a 15ft cube of water.

Trying to be 'clever' with ambiguously worded rules like this will only work if the DM is playing along. That's why you stick to something too obvious to rule out, like dropping 94 tons of water on someone is gonna hurt because dropping 94 tons of anything on someone is gonna hurt.

30. ## Re: Dust of Dryness Goes Nuclear

While not QUITE as good, you can get a lot of the same result by simply throwing a full barrel of water at them (or rolling one down the hill, as I have done).

The fire elemental either destroys the barrel, dumping the water on them, or super-heats the barrel, popping its lid and exploding the water inside them.

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