Cloud

Version 0.30: This article may not be up to date for the latest stable release of Crawl.

Clouds are temporary, non-solid dungeon features, which occupy tiles. Some clouds cause damage or status effects, while others do nothing more than block line of sight. Some areas of the dungeon will perpetually create clouds.

Clouds will dissipate on their own over time. Player-generated clouds will disappear the moment the cloud leaves your line-of-effect (similar to line of sight, but cloud can dissipate behind transparent walls).

No clouds can be placed on tiles where a cloud already exists. For example, placing a cloud of smoke will prevent a more dangerous cloud from appearing on that tile.

Regardless of other properties, players that follow Qazlal or wear the Robe of Clouds are immune to the harmful effects of all clouds.

Atmospheric

Atmospheric clouds are merely decorative. They prevent other clouds from spawning, but have no other effect. Several varieties exist, including sparse dust, thin mist, or magical condensation.

Created by certain effects, usually part of the Dungeon floor or a vault. Jumping spiders leave behind clouds of dust, while Xom can give followers a trail of magical condensation.

Opaque

Opaque clouds can block line of sight. Your line of sight stops after two opaque clouds in any direction. Many opaque clouds have no other special effect. Some clouds are opaque and have other effects.

Like atmospheric clouds, there are multiple varieties of opaque clouds, including several colours of smoke, translocational energy, golden dust, salt, white fluffiness, and ink.

They are somewhat rarer than atmospheric clouds. Translocational energy is created, in small amounts, by Translocations magic, teleports, and summons. Scrolls of fog create smoke, which spreads to adjacent tiles. Many effects like Dithmenos' Bleed Smoke, Wu Jian's Heavenly Storm, and the Cloak of the Thief create opaque clouds.

Unlike other clouds, a kraken's ink will only affect water tiles.

Damaging

Steam

Steam clouds are full of scaldingly hot mist. They inflict steam damage on anything standing on them. Creatures with rSteam or rF+ are immune to steam damage. In addition, these clouds are opaque and will block LOS.

Steam clouds are created when Fire Magic (including a wand of flame) passes over water, or when icy projectiles pass lava. It is also created when water is adjacent to lava, or in certain vaults.

• Damage: 2d(16)/2 - 1 steam per turn

Negated entirely by rSteam or rF+

Flame

Clouds of flame are tiles which have caught on fire, which deal fire damage. Certain icy beams, like Bolt of Cold, will put out flame clouds.

Created by Fire Storm, red draconian or Dragon Form breath attack, demonspawn with Ignite Blood, Qazlal worshippers, or a condenser vane, Ignite Poison turns poison clouds into flames, and creates flames from Eringya's Noxious Bog.

• Damage: 2d(23)/2 + 9 fire per turn (against players)

2d(16)/2 + 5 fire per turn (against monsters)

Resisted by rF+. Players with demonspawn mutation, Ignite Poison are immune.

Spreading flames

Spreading flames are a special type of flame cloud, created when trees are set on fire. They act like regular flames, but periodically create new flames in tiles next to them, potentially lighting other trees on fire.

• Damage: Same as clouds of flame.

Freezing vapour

Freezing clouds are tiles filled with brutally cold mist. They deal cold damage. It can be dispersed by strong Fire Magic, such as Fireball or Bolt of Fire.

Created by Freezing Cloud, a condenser vane, Qazlal worshippers, and the unrand axe Frostbite. Simulacra create an ice cloud when destroyed. For monsters, using Bolt of Cold over water, or the spell Glaciate, creates frost clouds.

• Damage: 2d(23)/2 + 9 fire per turn (against players)

2d(16)/2 + 5 fire per turn (against monsters)

Resisted by rC+. Players wielding Frostbite are immune

Acidic fog

Acidic fog is a hideously dangerous type which inflicts acid damage, and causes the corrosion status. Creatures with corrosion resistance are fully immune. Fortunately, monsters with rCorr are very rare outside of the Slime Pits

Created by a condenser vane at high power.

• Damage: 2d(23)/2 + 9 acid per turn (against players)

2d(16)/2 + 5 acid per turn (against monsters)

Negated entirely by rCorr.

Blessed fire

Clouds of blessed fire burn with holy, cleansing light. Deals more damage to demons and the undead. Only creatures consecrated by or in service to the good gods are immune to their effects. In addition, these clouds are opaque and will block LOS.

Created by pearl dragons and ophans. Appears in a few vaults.

• Damage: 2d(19)/2 + 7 holy per turn (against players)

1d12 + 3 holy per turn (against monsters)

Affected by holy resistance.

Negative energy

Clouds of negative energy deal negative energy damage, and inflicts the drain status. Negative energy resistance applies. Creatures immune to negative energy are immune to this cloud, including demons, nonliving, undead, and players with rN+++.

Created by a condenser vane.

• Damage: 2d(23)/2 + 9 negative energy per turn (against players)

2d(16)/2 + 5 negative energy per turn (against monsters)

Resisted by rN+.

Spectral flames

Spectral flames burn with the chill fires of undeath. They deal partially-irresistible negative energy damage. In addition, they summon spectral things, which immediately attack creatures hostile to the cloud's creator. Undead creatures are immune to the damage.

Spectral flames are only ever created by monsters: ghost crabs and revenants can both create banks of spectral fire.

• Damage per turn: 2d(15)/2 + 3 partial negative energy

Undead and Yredelemnul worshippers are immune to damage.

Thunder

Clouds of thunder (storm clouds) deal electric damage, and are resisted by electricity resistance.

Created by condenser vanes, Qazlal worshippers, or the unrand robe of Clouds.

• Damage: ? electric per turn (~18 dmg/turn average)

Resisted by rElec.

Blastmotes

Created by the spell, Volatile Blastmotes. When a creature steps on its tile, or when hit by Fire Magic, it will explode, dealing damage.

• Damage: See Volatile Blastmotes

Whirling frost

Clouds of whirling frost are created by the spell, Polar Vortex. They deal heavy, partially irresistible cold damage, lift creatures into flight, and causes creatures to move counter-clockwise from the caster. In addition, they can destroy trees.

• Damage: See Polar Vortex

50% resisted by rC+.

Creatures who are currently casting Polar Vortex are immune.

Status

Calcifying dust

Clouds of calcifying dust inflict the Petrifying status on any creature that stands on them. Nonliving or insubstantial creatures are immune. In addition, these clouds are opaque and will block LOS.

Players can only be affected by these clouds if they end their turn inside one. If you move outside of dust the moment it appears, then you won't get petrified.

Catoblepae belch forth clouds of calcifying dust at their prey, affecting friend and foe alike (though are immune to the effects themselves).

Noxious fumes

Clouds of noxious fumes (also known as mephitic clouds) are mildly toxic and foul-smelling gases. Anything caught in one is confused for several turns; creatures with higher HD are less likely to be confused. Can be turned into flame clouds via Ignite Poison.

Created by the Mephitic Cloud spell, condenser vane, green player draconian breath, and swamp drakes.

• Status: (21 - HD) in 21 chance to confuse monsters.

rPois gives immunity

Poison

Poison clouds are tiles filled with highly poisonous gas. Creatures with poison resistance are fully immune. Can be turned into flame clouds via Ignite Poison.

Created by a scroll of poison, condenser vanes, or player nagas with the Spit Poison 2 mutation. Swamp dragons, gold dragons, enemy green draconians, and green deaths breathe these.

• Damage: 1d10 - 1 poison (status)

Additional poison status

rPois gives immunity

Miasma

Clouds of miasma (also known as foul pestilence) are dangerous banks of corrupt fog. Vulnerable creatures take damage, are poisoned, and become slowed. Nonliving and undead creatures are immune; poison resistance stops the poison, and stasis stops the slow.

You can create miasma clouds with Cigotuvi's Dreadful Rot or the demonspawn mutation, Foul Stench. Death drakes, ushabtiu, and putrid mouths can breathe them. Tainted leviathans generate a ring of miasma. They can appear in certain Swamp:4 vaults.

• Damage: 1d12 - 1 poison (status)

rMiasma gives immunity, as does demonspawn mutation Foul Stench.

Mutagenic fog

Mutagenic fog is composed of raw, uncontrolled magic. These clouds inflict heavy magic contamination to players, which can cause bad mutations. Monsters are instead polymorphed every turn they stay inside one.

These clouds are usually only found in vaults. Cigotuvi's Fleshworks in particular has several rooms filled with mutagenic fog.

Seething chaos

Formed from the unpredictable forces of pure chaos, clouds of seething chaos produce effects similar to being hit with a weapon of chaos on any creature that enters them.

Created by apocalypse crabs, and appear when a chaos spawn is killed.

Degeneration

Clouds of degeneration rapidly wither creatures that stand in them, repeatedly inflicting the effects of a potion of degeneration.

Spawns in the wizlab, Alistair's Party Mansion.

Rain

Rain clouds create water over time. Solid ground becomes shallow water, and shallow water becomes deep water. This effect is temporary. Does not harm creatures.

Only created by sky beasts, who create rain when turning invisible or becoming visible again.

History

• Prior to 0.30, clouds of thunder would create "strikes of thunder"; they dealt less damage over time, but caused a damaging thunder strike every so often. This was bugged, where faster actions would trigger lightning strikes less often. Also, the "smouldering flames" cloud, created by Conjure Flame, was removed.
• Prior to 0.28, noxious fumes dealt minor poison damage, and clouds of degeneration did not exist. Also, rain and storm clouds would cause rain, which hurt water-vulnerable creatures.
• Prior to 0.27, unbreathing protected against certain clouds. The Hurl Damnation demonspawn mutation provided flaming cloud immunity. Thunder clouds would create loud noises. Also, in this version, Tornadoes were replaced with Polar Vortices
• Prior to 0.19, player-created clouds did not vanish instantly when out-of-sight, instead they just dissipated faster.
• Prior to 0.15, clouds of mutagenic fog directly caused mutations rather than causing heavy magical contamination.
• Prior to 0.14, clouds could be placed outside of the caster's LOS, and lasted normal duration. 0.14 also added clouds of negative energy, thunder, and acid.
• 0.13 added spectral flames.