Caustic gas

Caustic Gas

You can feel the purple gas eating at your flesh.

Purple caustic gas is produced by bloats, traps, and Potions of Caustic Gas. It is the most commonly encountered gas and it injures any monster or adventurer caught in it.

Any monster caught in caustic gas will lose 1/15th of its health every turn, or at least 1hp if it doesn't even have 15. Steam, which is common down deep, behaves exactly the same except that steam dissipates quickly and is not flammable.

Like other gasses, caustic gas' duration is directly tied to how far it is able to disperse. If done in a wide open area with no walls, the gas will expand as far as it is naturally capable, and because of that expansion, the cloud will dissipate relatively quickly. However, if the gas is released in a small, sealed off room, the gas will linger for a substantial amount of time due to how condensed it is. This makes it most deadly when used in rooms/areas with very little open floor space and with, preferably, only one exit point (i.e. goblin warrens). If you stand in that choke point on the peripheries of the cloud, you can easily dispatch the injured enemies as they're forced to come to you, and any others will be forced to queue up and wait in the deadly fumes.

Caustic gas is flammable, thus an adventurer should be careful if it occurs near any flame source, including sputtering wall torches or burning creatures. A player with a Staff of Firebolt, Potion of Incineration, or an incendiary dart can use it to plunge unsuspecting monsters into fiery chaos. This is a great option to extend the damage of the cloud if they have a way to escape it.

It is often wiser to burn caustic gas than to be caught in it, even if it sets you alight. Burning deals an average of 2 hp damage per turn and only lasts seven turns.