Brown Mold silliness

[virgil]

I can't be the only one that considers brown mold to be ridiculous in just about every way, can I?

Brown mold feeds on warmth, drawing heat from anything around it. It normally comes in patches 5 feet in diameter, and the temperature is always cold in a 30-foot radius around it. Living creatures within 5 feet of it take 3d6 points of nonlethal cold damage. Fire brought within 5 feet of brown mold causes it to instantly double in size. Cold damage, such as from a cone of cold, instantly destroys it.

How does something like this even work, thermodynamically? It seems to break every law of science and common sense and game balance there is.

Does it double in surface area covered, or does it get twice as thick, or both? Does it double only the mold within 5' of the flame, or does it double the entire contiguous colony? Notice how it doesn't do anything to stop fire from burning, especially since it only does nonlethal damage, so does a dropped torch or something crazy like a flaming sphere result in the entire dungeon complex covered in brown mold (or a 10' radius solid sphere if it only doubles within reach). What happens if it ends up next to a magically eternal source of flame, or powers forbid, in the Plane of Fire?

Or is just a mediocre Gygaxian legacy hazard with purposefully vague text so that no player will be able to predict what their DM will do with it?

[Crissa]

It's just one of those things, it magically transfers your electron vibration to itself, and transforms that energy into matter. It's so good at this that a simple source of combustion will feed it, and even though it's mindless, it won't devour the flame completely - it doesn't want to kill you, just... Borrow some heat. Until you die of smothering or being unconscious too long. It's magic.

This is one of those things that you realize that in 3e and 4e they've tried simplifying things to the point that they no longer make sense. The damage wasn't nonlethal in 2e, was it?

-Crissa

[Leress]

Here is the entry for brown mold from 2ed:
AC: 9
Special attacks: Freezing
Special defenses: Absorb Heat
XP : 15

Brown mold is found in damp subterranean areas, such as caverns and caves. It is light to golden brown in color. Brown mold feeds by absorbing heat, even body heat; where brown mold grows, the temperature is below average. Direct sunlight or ultraviolet light kills it.

If a warm-blooded creature comes within 5 feet of a brown mold, the mold drains heat equal to 4d8 points of damage from its victim, per round. A ring of warmth provides complete protection against this attack. Brown mold grows instantly from heat. If a torch is used in its vicinity, it doubles in size; if flaming oil is use, it quadruples, and fireball-type spell cause it to grow eight-fold.

Brown mold is not fed by cold light sources (e.g., light, faerie fire). The only magic that affects it are disintegrate (which destroys it), plant-affecting magic, and cold spells. Ice storms or walls of ice cause it to go dormant for 5d6 turns. A cold wan, white dragon breath, or a cone of cold kills it. Brown mold does not affect cold-using creatures such as white dragons, winter wolves, ice toads, etc.

The entry is more vague about the size of a patch of brown mold, and says its diet is just heat. So all 3ed do was make it less deadly.

[hogarth]

How does something like this even work, thermodynamically?

You fail at magic.

Or is just a mediocre Gygaxian legacy hazard with purposefully vague text so that no player will be able to predict what their DM will do with it?

That sounds about right.

My interpretation: a 5' x 5' patch becomes a 10' x 5' patch.

[Lokathor]

Suggestion: Each patch within range of the flame can automatically spawn another patch adjacent to it on it's turn. If there's no more room for new patches then that segment can't spawn anymore. Simple and easy, even if it's not quite what the book says.

Also, Continual Flame wouldn't affect a brown mold, since it doesn't provide heat.

[K]

I always wondered why people didn't just get a pole with a bucket on it and carry around patches of brown mold as a weapon.

[Koumei]

Apparently they're great to fill your undead with, if you're sending them out on suicide* missions. Because people prefer to use fire against undead. I think you see what happens next.

And "Crazy Wizard wants to open Gate to Plane of Fire, throw a brown mold in" sounds like a hilarious doomsday plot. If the game has not utilised them up to that point, you can even have life continue as normal if the players fail: he throws it in, it doubles in size, and that's it, no more doubling.

"Well, that was disappointing."

*Is it suicide if it's an undead? Particularly unintelligent undead like skeletons and zombies? That's really just self-disposal, like a more aggressive form of decomposition.

[Quantumboost]

Also, Continual Flame wouldn't affect a brown mold, since it doesn't provide heat.

There are other magically eternal sources of fire. Using permanency on a wall of fire is the example that comes to mind.

[Crissa]

Once it doubles, the double is probably no longer in range of the fire.

...And they do probably live happily in the plane of fire.

-Crissa

[Lokathor]

good thing it's infinite in scope.

sadly, this is an easy way to destroy any established location on the plane of fire.

[Crissa]

I don't know if 'destroy' is the word I'd use. It'd make pockets of less-hot which might be pretty nice in comparison.

-Crissa

[Prak]

I don't know if 'destroy' is the word I'd use. It'd make pockets of less-hot which might be pretty nice in comparison.

-Crissa

except you'd then be walking on growing, living, cold carpet.

[Archmage]

I suspect that there is no place on the plane of fire that is not within five feet of a fire. Any brown mold thrown in would immediately grow, continue to be within five feet of fire, grow, etc., setting off a chain reaction that engulfed the entire plane. It would become the plane of brown mold. An interesting planar environmental catastrophe. It seems obvious enough, which makes me wonder how there manages to be a plane of fire in any setting where someone discovers this kind of interaction, assuming standard rules apply.

[Prak]

I suspect that there is no place on the plane of fire that is not within five feet of a fire. Any brown mold thrown in would immediately grow, continue to be within five feet of fire, grow, etc., setting off a chain reaction that engulfed the entire plane. It would become the plane of brown mold. An interesting planar environmental catastrophe. It seems obvious enough, which makes me wonder how there manages to be a plane of fire in any setting where someone discovers this kind of interaction, assuming standard rules apply.

you also have to assume that sentients are assholes with nothing better to do than fuck with other peoples' homes.


...Look, I'm not saying it's a stretch...

[Archmage]

However, since the mold explicitly expands instantly, it covers the entire plane before anyone there (including the majority of its efreet population) has any chance to do anything about it. (There might be some areas on the plane of fire that are somehow shielded or otherwise protected from the brown mold apocalypse.)

So you pitch in a few spores carelessly and you wind up with, if necessary, superluminal mold growth. Depending on how you interpret the ability to destroy it, it's either one entire organism (in which case 1 point of damage from a ray of frost eliminates an entire plane worth of mold) or you only destroy the immediate area touched by a cold effect (in which case you slowly clean up the plane with cold spells; if the heat from before doesn't automagically regenerate, you might wind up with a plane of mostly empty space that used to be on fire). It's probably best not to think too hard about this unless you're inclined to enjoy weird D&D physics-shattering hypotheticals.

The bad news is that I imagine all the efreet in the City of Brass can survive 3d6 nonlethal damage, so they plane shift to your location and obliterate you in response to your chilling act of genocide.

[Lokathor]

It expands probably only once a round. Even at that rate, the plane is infinite. It doesn't matter how fast it grows, it'll never consume all of it.

[K]

Doesn't Brown mold go dormant in sunlight?

[virgil]

While that might have been the case in 2E (don't have the books), that's only really the case for Yellow Mold. Green Slime just dies in sunlight.

[Nicklance]

Goddammit now I have an awesome idea for my DM's campaign.

[Count Arioch the 28th]

Wouldn't destroying the Elemental plane of Fire result in the heat-death of the entire multiverse? Unless I'm misunderstanding psuedo-mystical crap.

[Maxus]

I shared this with someone.

Their response?

Giving me ideas...Seal it up in something breakable.
Tie it to a vial of Alchemists Fire...
Tied to a flask of oil to keep it burning for a bit...

Also, Fire Mages. Or fiends who main the Fire/Pyre spheres.

[K]

I assume that Brown Mold has some kind of hard cap. Otherwise, you could make entire fields of the crap with some torches and a little free time.

[Username17]

Brown mold is one of my favorite shrink item items.

-Username17

[Aktariel]

However, since the mold explicitly expands instantly, it covers the entire plane before anyone there (including the majority of its efreet population) has any chance to do anything about it....

superluminal mold growth.

Especially since the plane is infinite... so it expands infinitely fast.

Presuming of course that it does so instantaneously, and not once/round like people are arguing.

[Grek]

Also that there is absolutely nothing that can do ice damage to it anywhere on the plane.