Good mutations

Version 0.21: This article may not be up to date for the latest stable release of Crawl.

This is a list of all of the good mutations which can be acquired. While most of these are useful to any character, some may in fact be significantly detrimental to some builds. Even so, they are included here because "good mutation" is a technical term in the game, not a qualitative judgment. Any of these can be acquired through any source of good mutations, such as a potion of beneficial mutation.

Offensive

Some of these mutations will prevent your character from wearing items in certain equipment slots. While this penalty may outweigh the gain your character receives, bear in mind that races which cannot use those slots (ogres, trolls, felids, etc.) lose nothing.

Fangs

Rank	Effect	Flavor
1	Auxiliary bite attack.	You have sharp teeth.
2	Improved auxiliary bite attack.	You have very sharp teeth.
3	Superior auxiliary bite attack.	You have razor-sharp teeth.
Damage: 1 + (2 * rank) Chance: 40% * (30 + XL)/59 per melee attack Having Acidic Bite adds 4 base damage and 2d4 acid damage. If Vine Stalker, add XL/3 damage, chance increased to 100% * (30 + XL)/59, and grants antimagic.
Species notes: Vampires and Felids start with rank 3. Gnolls have rank 1. Vine Stalkers start with rank 2 and upgrade to rank 3 at XL 8.
Good mutation, Demonspawn mutation

Beak

Rank	Effect	Flavor
1	Auxiliary peck attack. Prohibits helmet.	You have a beak for a mouth.
Damage: 6 Chance: 66% * (30 + XL)/60 per melee attack
Species notes: Tengu start with Beak.
Good mutation

Claws

Rank	Effect	Flavor
1	+2 unarmed base damage. Negated by gloves.	You have sharp fingernails.
2	+4 unarmed base damage. Negated by gloves.	You have very sharp fingernails.
3	+6 unarmed base damage. Prohibits gloves.	You have claws for hands.
Using Unarmed Combat with level 3 Claws will decapitate hydra heads.
Species notes: Ghouls start with rank 1 and Trolls start with rank 3. Octopodes cannot gain claws.
Good mutation, Demonspawn mutation

Horns

Rank	Effect	Flavor
1	Auxiliary headbutt attack. Prohibits helmets.	You have a pair of small horns on your head.
2	Improved auxiliary headbutt attack. Prohibits helmets.	You have a pair of horns on your head.
3	Superior auxiliary headbutt attack. Prohibits all headgear.	You have a pair of large horns on your head.
Damage: 5 + (3 * rank) Chance: 66% * (30 + XL)/59 per melee attack Minotaurs may retaliate against enemies with headbutts.
Species notes: Minotaurs start with rank 2, and Oni start with rank 1. Demonspawn can gain horns as a body slot option. Octopodes cannot gain horns.
Good mutation, Demonspawn mutation

Hooves

Rank	Effect	Flavor
1	Auxiliary kick attack. Negated by boots.	You have large cloven feet.
2	Improved auxiliary kick attack. Negated by boots.	You have hoof-like feet.
3	Superior auxiliary kick attack. Prohibits boots.	You have hooves in place of feet.
Damage: 5 + (5/3 * rank) Chance: 100% * (30 + XL)/59 per melee attack
Species notes: Demonspawn can gain hooves as a body slot option. Nagas, merfolk, felids, and octopodes cannot gain hooves.
Good mutation, Demonspawn mutation

Talons

Rank	Effect	Flavor
1	Auxiliary kick attack. Negated by boots.	You have sharp toenails.
2	Improved auxiliary kick attack. Negated by boots.	You have razor-sharp toenails.
3	Superior auxiliary kick attack. Prohibits boots.	You have claws for feet.
Species notes: Tengu start at rank 3. Demonspawn can gain talons as a body slot option. Nagas, merfolk, felids, and octopodes cannot gain talons.
Good mutation, Demonspawn mutation

Defensive

Tough Skin

Rank	Effect	Flavor
1	+1 AC	You have tough skin.
2	+2 AC	You have very tough skin.
3	+3 AC	You have extremely tough skin.
Species notes: Oni and trolls start at rank 1.
Good mutation

Shaggy Fur

Rank	Effect	Flavor
1	+1 AC	You are covered in fur.
2	+2 AC	You are covered in thick fur.
3	+3 AC, rC+	Your thick and shaggy fur keeps you warm.
Species notes: Trolls and felids start at rank 1; felids gain rank 2 at XL 6 and rank 3 at XL 12.
Good mutation

Camouflage

Rank	Effect	Flavor
1	+40 Stealth	Your skin changes colour to match your surroundings.
2	+80 Stealth	Your skin blends seamlessly with your surroundings.
3	+120 Stealth	Your skin perfectly mimics your surroundings.
Species notes: Octopodes start at rank 1.
Good mutation

Resistances

Fire Resistance

Rank	Effect	Flavor
1	rF+	Your flesh is heat resistant.
2	rF++	Your flesh is very heat resistant.
3	rF+++	Your flesh is almost immune to the effects of heat.
Species notes: Red draconians develop rank 1 upon changing color.
Good mutation

Cold Resistance

Rank	Effect	Flavor
1	rC+	Your flesh is cold resistant.
2	rC++	Your flesh is very cold resistant.
3	rC+++	Your flesh is almost immune to the effects of cold.
Species notes: White draconians develop rank 1 upon changing color.
Good mutation

Electricity Resistance

Rank	Effect	Flavor
1	rElec	You are resistant to electric shocks.
Species notes: Gargoyles start with rank 1. Black draconians develop rank 1 upon changing color.
Good mutation

Poison Resistance

Rank	Effect	Flavor
1	rPois	Your system is resistant to poisons.
Species notes: Nagas start with rank 1. Green draconians develop rank 1 upon changing color. Gargoyles are instead immune to poison.
Good mutation

Magic Resistance

Rank	Effect	Flavor
1	Willpower+	You are resistant to hostile enchantments.
2	Willpower++	You are highly resistant to hostile enchantments.
3	Willpower+++	You are extremely resistant to the effects of hostile enchantments.
Good mutation

Clarity

Rank	Effect	Flavor
1	Clarity	You possess an exceptional clarity of mind.
Good mutation

Mutation Resistance

Rank	Effect	Flavor
1	66.6% resistance to further mutation (50% for transient mutations).	You are somewhat resistant to further mutation.
2	66.6% resistance to further mutation (50% for transient mutations). Mutation removal fails 50%.	You are somewhat resistant to both further mutation and mutation removal.
3	100% resistance to further mutation. Mutation removal fails 100%.	You are almost entirely resistant to both further mutation and mutation removal.
This mutation stacks with other sources of mutation protection such as Zin and the hat of the Alchemist multiplicatively. Rank 3 of the mutation can only be removed by Jiyva, Xom (retribution or not), Zin (retribution), or by magical contamination.
Species notes: Prior to their 0.27 removal, Halflings started at rank 1.
Good mutation

Movement

Blink

Rank	Effect	Flavor
1	Gain the Blink ability. Each use inflicts damage equal to 5% of your max HP.	You can translocate small distances at will.
Good mutation

Perception

Acute Vision

Rank	Effect	Flavor
1	Grants see invisible.	You have supernaturally acute eyesight.
Species notes: Nagas, spriggans, vampires, and felids start with this.
Good mutation

Antennae

Rank	Effect	Flavor
1	Shows the location of all invisible enemies in line of sight. Detects all monsters within 3 tiles, even through walls or opaque clouds. Prohibits helmets.	You have a pair of small antennae on your head.
2	Range increases to 5 tiles. Prohibits helmets.	You have a pair of antennae on your head.
3	Range increases to 7 tiles. Grants see invisible. Prohibits all headgear.	You have a pair of large antennae on your head.
When playing in console mode, creatures not in line of sight are revealed as { or { glyphs, depending on whether the entity is hostile or friendly. In tile mode, they appear as icons which similarly indicate hostility. Mimics will be identified as soon as they enter your antennae range.
Species notes: Formicids start with rank 3. Demonspawn can gain antennae as a body slot option.
Good mutation, Demonspawn mutation

Passive Mapping

Rank	Effect	Flavor
1	Reveal random tiles outside LOS	You passively map a small area around you.
2	Reveal more random tiles outside LOS	You passively map the area around you.
3	Reveal many random tiles outside LOS	You passively map a large area around you.
Good mutation

General

Evolution

Rank	Effect	Flavor
1	Gain mutations until trait expires.	You have hidden genetic potential.
2	Same as previous level, though lasts longer.	You have great hidden genetic potential.
Triggers about once per XL, providing another good mutation. Every two activations, it reduces its level by one. Changed in 0.28, see the Evolution page for more details.
Good mutation

Wild Magic

Rank	Effect	Flavor
1	Spell Power+, Spell Success-	Your spells are a little harder to cast, but a little more powerful.
2	Spell Power++, Spell Success--	Your spells are harder to cast, but more powerful.
3	Spell Power+++, Spell Success---	Your spells are much harder to cast, but much more powerful.
Each level gives +30% (additively stacked, then multiplied) to raw spellpower and +4% (additive) to raw spell failure rate. Generally, you will get less than +30% actual power. You will get less than +4% failure if your failure is already low (< 8%), but slightly more if your failure is high.
Good mutation

Improved Attributes

Rank	Effect	Flavor
1	+4 to STR, INT or DEX -1 to the other two stats.	Your muscles are strong. Your mind is acute. You are agile.
2	+8 to STR, INT or DEX -2 to the other stats	Your muscles are very strong. Your mind is very acute. You are very agile.
It's possible to gain this mutation for multiple different stats, but each stat may have up to 2 levels.
Good mutation

Regeneration

Rank	Effect	Flavor
1	HP regeneration rate +0.8 HP/turn	Your natural rate of healing is unusually fast.
2	HP regeneration rate +1.6 HP/turn	You heal very quickly.
3	HP regeneration rate +2.4 HP/turn	You regenerate.
Each level healed 1 HP/turn in 0.27, and 0.4HP/turn prior. Excludes Slow Metabolism prior to 0.26.
Species notes: Trolls and Vine Stalkers start at rank 1.
Good mutation

Robust

Rank	Effect	Flavor
1	+10% max HP	You are robust.
2	+20% max HP	You are very robust.
3	+30% max HP	You are extremely robust.
Good mutation, Demonspawn mutation

High MP

Rank	Effect	Flavor
1	+10% max MP	You have an increased reservoir of magic.
2	+20% max MP	You have a considerably increased reservoir of magic.
3	+30% max MP	You have a greatly increased reservoir of magic.
Species notes: Demigods start at rank 1.
Good mutation

Scales

Draconian scales function differently from those below: their AC increases as they level, and they may gain other resistances besides their scales. As such, they cannot develop any of these mutations. As they level, non-"monstrous" demonspawn naturally receive three ranks of a single scales mutation. They may still gain scales through other means of mutation, but only in the category that they would eventually get on their own.

No character can have more than three total ranks of scales-type mutations at a time (e.g. if you already have Molten Scales 2, you could develop Large Bony Plates 1, but not Large Bony Plates 2). A naga's serpentine lower half counts as one rank of a separate scales mutation, so they can only have up to two ranks of other types of scales at a time.

Molten Scales

Rank	Effect	Flavor
1	+2 AC	You are partially covered in molten scales.
2	+3 AC	You are mostly covered in molten scales.
3	+4 AC, rF+	You are completely covered in molten scales.
Good mutation, Demonspawn mutation

Icy Blue Scales

Rank	Effect	Flavor
1	+2 AC	You are partially covered in icy blue scales.
2	+3 AC	You are mostly covered in icy blue scales.
3	+4 AC, rC+	You are completely covered in icy blue scales.
Good mutation, Demonspawn mutation

Slimy Green Scales

Rank	Effect	Flavor
1	+2 AC	You are partially covered in slimy green scales.
2	+3 AC	You are mostly covered in slimy green scales.
3	+4 AC, rPois	You are completely covered in slimy green scales.
Good mutation, Demonspawn mutation

Thin Metallic Scales

Rank	Effect	Flavor
1	+2 AC	You are partially covered in thin metallic scales.
2	+3 AC	You are mostly covered in thin metallic scales.
3	+4 AC, rElec	You are completely covered in thin metallic scales.
Good mutation, Demonspawn mutation

Yellow Scales

Rank	Effect	Flavor
1	+2 AC	You are partially covered in yellow scales.
2	+3 AC	You are mostly covered in yellow scales.
3	+4 AC, rCorr	You are completely covered in yellow scales.
Good mutation, Demonspawn mutation

Rough Black Scales

Rank	Effect	Flavor
1	+2 AC, -1 DEX	You are partially covered in rough black scales.
2	+5 AC, -2 DEX	You are mostly covered in rough black scales.
3	+8 AC, -3 DEX	You are completely covered in rough black scales.
Good mutation, Demonspawn mutation

Rugged Brown Scales

Rank	Effect	Flavor
1	+1 AC, +3% HP	You are partially covered in rugged brown scales.
2	+2 AC, +5% HP	You are mostly covered in rugged brown scales.
3	+3 AC, +7% HP	You are completely covered in rugged brown scales.
Good mutation, Demonspawn mutation

Iridescent Scales

Rank	Effect	Flavor
1	+2 AC	You are partially covered in iridescent scales.
2	+4 AC	You are mostly covered in iridescent scales.
3	+6 AC	You are completely covered in iridescent scales.
Good mutation

Large Bone Plates

Rank	Effect	Flavor
1	+4 SH	You are partially covered in large bone plates.
2	+6 SH	You are mostly covered in large bone plates.
3	+8 SH	You are completely covered in large bone plates.
Good mutation, Demonspawn mutation

Repulsion Field

Rank	Effect	Flavor
1	+2 EV	You are surrounded by a mild repulsion field.
2	+3 EV	You are surrounded by a moderate repulsion field.
3	+4 EV, Repel Missiles	You are surrounded by a strong repulsion field.
Prior to 0.19, the EV bonus applied even when paralysed, sleeping, etc.
Good mutation, Demonspawn mutation

Thin Skeletal Structure

Rank	Effect	Flavor
1	+2 DEX, +25 Stealth	You have a somewhat thin skeletal structure.
2	+4 DEX, +50 Stealth	You have a moderately thin skeletal structure.
3	+6 DEX, +75 Stealth	You have an unnaturally thin skeletal structure.
Good mutation, Demonspawn mutation
In earlier versions of Crawl, this mutation also reduced strength by 1 per rank.

Species exclusive

These mutations may only be acquired by certain species.

Poison Breath

Rank	Effect	Flavor
1	Grants the Spit Poison ability.	You can spit poison.
2	Upgrades to Breathe Poison.	You can exhale a cloud of poison.
Species notes: Exclusve to Nagas, who start at level 1.
Good mutation

Stinger

Rank	Effect	Flavor
1	Adds damage and Venom to auxiliary tail slap.	Your tail ends in a poisonous barb.
2	Adds more damage to auxiliary tail slap.	Your tail ends in a sharp poisonous barb.
3	Adds most damage to auxiliary tail slap.	Your tail ends in a wickedly sharp and poisonous barb.
Damage: 6 + (4 if you have Armoured Tail) + (2 * rank) Chance: 50% * (30 + XL)/59 per melee attack
Species notes: Exclusive to Nagas, Armataurs, and Draconians, who can get this randomly. Green draconians gain rank 1 at XL14 (and may gain more).
Good mutation

Big Wings

Rank	Effect	Flavor
1	You now fly permanently.	You have big, strong wings, capable of bearing you through the air.
Prior to 0.27, flight could be toggled on or off. Prior to 0.17, the flight granted by this mutation was temporary if it wasn't from your species.
Species notes: Exclusive to draconians and gargoyles. Black draconians and gargoyles naturally develop it at XL 14, though other draconians can acquire it as a random mutation.
Good mutation

Tentacle Spike

Rank	Effect	Flavor
1	Adds damage to auxiliary tentacle slap.	One of your tentacles bears a spike.
2	Adds more damage to auxiliary tentacle slap.	One of your tentacles bears a nasty spike.
3	Adds most damage to auxiliary tentacle slap.	One of your tentacles bears a large vicious spike.
Damage: 5 + rank Chance: 100% * (30 + XL)/59 per melee attack
Species notes: Exclusive to octopodes. Octopodes may also temporarily induce rank 3 of this mutation with Beastly Appendage.
Good mutation

See Also

• Bad mutations
• Demonspawn mutations
• Jiyva mutations

History

Prior to 0.14 the Fast mutation was available as a random mutation and the Antennae mutation did not show invisible enemy indicators outside range 3 & 5 at ranks 1 & 2.

In 0.13, the Teleport Control, Strong Stiff, and Flexible Weak mutations were removed, and Improved Attributes was changed to only have 2 levels, each of which granted +2 to an attribute.