Mercury Vapours

Version 0.25: This article may not be up to date for the latest stable release of Crawl.

Mercury Vapours
Level	2
School1	Air
School2	Alchemy
Source(s)	Book of Vapours Young Poisoner's Handbook
Casting noise	2
Spell noise	0
Power Cap	50
Range	3
Flags	Not self, Target

Briefly transmutes the air around a target into gaseous mercury, poisoning those who breathe it in. Further, the target and adjacent creatures (living or otherwise) may be weakened by mere exposure to the alchemical substance.

Poisonous Vapours is a level 2 Poison/Air spell which attempts to place a smite-targeted poison cloud on an enemy in line of sight. At low spell power, the cloud itself may not last long enough to be visible, but the poison will nevertheless be stacked on the enemy.

Poisonous Vapours will fail to cast if:

• There is a non-poison cloud on the creature (this includes Mephitic Cloud), or
• The monster has poison resistance. This includes monsters wearing rings or armour that offer poison resistance.

Strategy

Poisonous Vapours is an excellent spell for Venom Mages to pick up at XL 2, as a more reliable, more damaging, longer-ranged Sting. The fact that it is level 2 and can't miss also makes it appealing for any character with a few free spell levels.

If a monster is already standing in a dangerous cloud, they generally disregard further clouds in order to close in on you. You can make use of this by creating other types of dangerous clouds (Conjure Flame, Freezing Cloud, a wand of clouds, etc.), then using Poisonous Vapors to prompt cautious monsters to walk into them.

Slow monsters are affected by clouds on their respective turns; due to Poisonous Vapours's extremely short duration, it can be difficult to use it on very slow creatures like worms.

History

• In 0.27, Poisonous Vapours directly poisons the target, rather than making a cloud.
• Poisonous Vapours was added in 0.20.