Mephitic Cloud

Version 0.31: This article may not be up to date for the latest stable release of Crawl.

Mephitic Cloud
Level	3
School1	Air
School2	Alchemy
School3	Conjuration
Source(s)	Book of the Senses Book of Vapours
Casting noise	3
Spell noise	15
Power Cap	100
Range	4
Flags	Area, Cloud, Dir or target, Needs tracer

Conjures up a short-lived cloud of noxious fumes, which may cause confusion in any creature not resistant to poison. Tougher, more experienced creatures are less likely to be affected. “Seit mehreren Jahren schon hatte die indische Cholera eine verstärkte Neigung zur Ausbreitung und Wanderung an den Tag gelegt. Erzeugt aus den warmen Moraesten des Ganges-Deltas, aufgestiegen mit dem mephitischen Odem jener üppig-untauglichen, von Menschen gemiedenen Urwelt- und Inselwildnis, in deren Bambusdickichten der Tiger kauert, hatte die Seuche in ganz Hindustan andauernd und ungewöhnlich heftig gewütet, hatte östlich nach China, westlich nach Afghanistan und Persien übergegriffen und, den Hauptstraßen des Karawanenverkehrs folgend, ihre Schrecken bis Astrachan, ja selbst bis Moskau getragen.” -Thomas Mann, _Der Tod in Venedig_, 1911.

Mephitic Cloud is a Level 3 Conjurations/Alchemy/Air Magic spell that creates up to a 3x3 cloud of noxious fumes, which will linger for several turns.

Alchemists and Hedge Wizards start with this spell.

Useful Info

Creates a bank of noxious fumes, affecting random tiles within a 3x3 radius from its release point. Higher spell power increases the amount of tiles affected. The clouds stay for a duration of 1d(power / 50) turns.

Anything standing in noxious fumes has a (21 - hit dice) / 21 chance per turn to become confused. Monsters with 21 or more hit dice have a flat 2% chance to be affected. Creatures that are resistant or immune to poison are immune to noxious fumes, anything with clarity is also immune.

Mephitic Cloud is very loud, making as much noise as Fireball. Since it can be targeted at an empty square, this increases the effective range by one.

Strategy

Confusion is a powerful effect: it prevents enemy spellcasting, gives a ~60% chance for melee attacks to target a wrong tile, and allows stabbing. Clouds last for multiple turns, so each cast can give multiple chances to confuse. And because it's a level 3 spell, it doesn't take that much investment to cast. Overall, despite Mephitic Cloud checking two properties (rPois and HD), it is a strong spell. Many of the most dangerous enemies in the early game, such as orc priests, centaurs, and all sorts of early uniques, are vulnerable.

In the late-game, this spell is less effective: more and more monsters have poison resistance, and the rest have high HD. But, by then, a level 3 spell will have done its work.

Aiming

If you are adjacent to a target, you can aim diagonally behind the target in order to not hit yourself (i.e. aim at the *):

.........  .........
...###...  ....###..
...#*#...  ....#*#..
...##Y...  ....Y##..
....@....  ....@....
.........  .........

By targeting diagonally behind the yak, you can catch it in the cloud radius without catching yourself.

If you have poison resistance, clarity, or are worshipping Qazlal, you are immune to clouds, so don't be afraid to blast yourself. Even if you aren't immune, risking self-confusion can be worth it. You can drink a potion of curing to end it; most enemies can't.

Tips & Tricks

• If you come across Ignite Poison, you can use Mephitic Cloud to create clouds of flame. You can confuse your enemies, then ignite them to inflict extra damage.
• Clouds cannot be placed on tiles that already have a cloud. So if you're immune to noxious fumes, you can cast Mephitic Cloud to prevent Petrifying Cloud or Chaos Breath clouds from affecting you.

History

• Prior to 0.28, noxious fumes would deal minor (0-2) poison-based damage while in them.
• Prior to 0.27, unbreathing creatures were immune to noxious fumes.
• Prior to 0.10, Mephitic Cloud guaranteed a 3x3 cloud.