Lava

[Ignominia]

Question about lava and movement.

Is lava a solid or a liquid? Can creatures swim through it AND stand on top of it? Should it be treated as if it was "soft earth" and everything has a "burrow" speed?

Im running an adventure next week that has the PC's entering a cavern filled with lava, and I need to know how the creatures they encounter (which are immune to fire damage) will interact with the lava.

EDIT: also, if you have a source for any ruling on this it would be super appreciated! Thanks!

[Invader]

I'm not sure if there's actual rules or not but I'd treat it as a liquid which can swim through at half speed.

[Cog]

Lava is still rock. Unless something is significantly more dense than rock, it will not sink in. For movement through it, I think strength would be key - set some sort of threshold Str above which you get half speed, and below which you're at 5' crawls if anything.

[Amaril Amakiir]

{Scrubbed}

[hymer]

Lava is still rock. Unless something is significantly more dense than rock, it will not sink in. For movement through it, I think strength would be key - set some sort of threshold Str above which you get half speed, and below which you're at 5' crawls if anything.

I'm not sure exactly what you refer to with 'dense' here.
Anyway, salt water is heavier (denser) than humans, which is why we float in it. That doesn't mean we can't swim it. Take something heavier, like mercury (about 13-14 times heavier than water), say a pool of it. If you wade out in it, you won't float until the weight you displace is greater than your whole weight. You could probably wade out to above the knees by quick guestimation. The same would go for lava (which is likely lighter than mercury), though you're right that it would probably be impossible to swim in it (though crossing it might be easier to do on your belly, using swim-like motions of arms and legs, than trying to walk in it). It also wouldn't always be entirely liquid, depending on the temperature.
On the other hand, it isn't possible to walk in it to begin with, so maybe reality doesn't matter too much for this.

[Eaglejarl]

Lava is a liquid: http://en.m.wikipedia.org/wiki/Lava This is supported in-game by the Wall of Magma spell, which states that casting create water on it will cause part of it to "solidify." Transmute Rock to Lava also uses the word "solidify," talking about when the lava cools down.

[Anxe]

It's just a really thick liquid. Kind of like honey. If your players have fire immunity, I'd be tempted to treat it like a quicksand trap instead. That kinda feels like a middle finger to the players. I like the idea of swimming through it at half the speed you could swim through water best. Plus, they have no visibility in the lava.

Other important question, does tremorsense work in the lava?

[Chronos]

According to actual scientific experiments, swimming speed is not affected by viscosity. Some scientists filled an entire swimming pool with some sort of solute that turned the water into slime, and then clocked the swim team in the stuff-- They swam about as fast as they do in water. They did, however, get tired a lot faster.

That said, due to its density, it's going to be impossible for most creatures to be completely submerged in lava. But this is a detail that I think the game writers were mostly ignorant of or ignored, since I'm pretty sure there are references to fire-immune creatures swimming under the surface of lava.

[HunterOfJello]

In the real world, it depends on the lava. Lots of lava that you see in videos is thick enough to the point that you could walk on it without sinking almost at all. Others types are much more fluid. Depends.

[(Un)Inspired]

I would say, make sure your creatures that travel in the lava have a specific "lava swim speed". Then, give them tremor sense so they can see through the stuff.

[Talya]

These are the best Lava rules I've seen, (http://www.scratchfactory.com/Resources/LavaBanners/LavaRules.pdf) adaptable to any game rule system. :smallbiggrin:

[eggynack]

These are the best Lava rules I've seen, (http://www.scratchfactory.com/Resources/LavaBanners/LavaRules.pdf) adaptable to any game rule system. :smallbiggrin:
Yeah, that pretty much covers all possible outcomes.