# Mold
A mold is a type of monster that appears in NetHack. All molds are part of the ​F fungus or mold monster class.

Contents

1 Common traits
2 Description
3 Strategy
4 Variants

4.1 SLASH'EM
4.2 SpliceHack

5 Encyclopedia entry
6 References

Common traits
Molds come in several colors, and each possesses a specific passive attack. All molds are sessile and vegan.
All molds except for the green mold have a small chance to convey poison resistance when eating their corpse or tin.

Description

Brown moldGreen moldRed moldYellow mold

F brown mold 

Difficulty

2

Attacks

Passive (level + 1)d6 cold

F brown mold 

Difficulty

2

Attacks

Passive (level + 1)d6 cold

Base level

1

Base experience

9

Speed

0

Base AC

9

Base MR

0

Alignment

0 (neutral)

Frequency (by normal means)

1 (Very rare)

Genocidable

Yes

Weight

50

Nutritional value

30

Size

Small

Resistances

Cold, poison

Resistances conveyed

Cold (3%), poison (3%)

A brown mold:

 does not breathe.
 cannot pick up items.
 has no eyes.

 has no limbs.
 has no head.
 is mindless.

 does not eat. (*)
 is neither male nor female.
 is normally generated hostile.

Reference

monst.c#line1299

The brown mold has a passive attack that causes cold damage. Repeatedly attacking a brown mold can cause it to multiply due to your body heat.

Eating a brown mold corpse is harmless and has a 3% chance of granting poison resistance or cold resistance.

F green mold 

Difficulty

2

Attacks

Passive (level + 1)d4 acid

F green mold 

Difficulty

2

Attacks

Passive (level + 1)d4 acid

Base level

1

Base experience

9

Speed

0

Base AC

9

Base MR

0

Alignment

0 (neutral)

Frequency (by normal means)

1 (Very rare)

Genocidable

Yes

Weight

50

Nutritional value

30

Size

Small

Resistances

Acid, petrification

Resistances conveyed

None

A green mold:

 does not breathe.
 cannot pick up items.
 has no eyes.

 has no limbs.
 has no head.
 is mindless.

 is acidic to eat.

 does not eat. (*)
 is neither male nor female.
 is normally generated hostile.

Reference

monst.c#line1313

The green mold has a passive attack that causes acid damage. The corpse of a green mold is acidic to eat.

Green molds are marked in the source as conveying stoning resistance, but no code actually reads this flag when their corpse is eaten, so they end up conveying nothing.[1]

F red mold 

Difficulty

2

Attacks

Passive (level + 1)d4 fire

F red mold 

Difficulty

2

Attacks

Passive (level + 1)d4 fire

Base level

1

Base experience

9

Speed

0

Base AC

9

Base MR

0

Alignment

0 (neutral)

Frequency (by normal means)

1 (Very rare)

Genocidable

Yes

Weight

50

Nutritional value

30

Size

Small

Resistances

Fire, poison

Resistances conveyed

Fire (3%), poison (3%)

A red mold:

 does not breathe.
 cannot pick up items.
 has no eyes.

 has no limbs.
 has no head.
 is mindless.

 does not eat. (*)
 is neither male nor female.
 is normally generated hostile.

 can be seen through infravision.

Reference

monst.c#line1320

The red mold is infravisible and has a passive attack that causes fire damage.

Eating a red mold corpse is harmless and has a 3% chance of granting poison resistance or fire resistance.

F yellow mold 

Difficulty

2

Attacks

Passive stun

F yellow mold 

Difficulty

2

Attacks

Passive stun

Base level

1

Base experience

8

Speed

0

Base AC

9

Base MR

0

Alignment

0 (neutral)

Frequency (by normal means)

2 (Quite rare)

Genocidable

Yes

Weight

50

Nutritional value

30

Size

Small

Resistances

Poison

Resistances conveyed

Poison (7%)

A yellow mold:

 does not breathe.
 cannot pick up items.
 has no eyes.

 has no limbs.
 has no head.
 is mindless.

 is poisonous to eat.

 does not eat. (*)
 is neither male nor female.
 is normally generated hostile.

Reference

monst.c#line1306

The passive attack of the yellow mold does no damage, and instead stuns you for (level + 1)d4 turns. Its corpse is poisonous and hallucinogenic to eat.

Strategy
Most molds can be safely left alone unless they are blocking your path. As you are not likely to possess the required resistance for each of their passives early in the game, if attacking them it is best to use any ranged weapon you have - even rocks or junk daggers will suffice. While your pet can also handle the mold, bad luck with weaker pets can result in them taking more damage passively than they can successfully deal.
Since brown and red mold corpses are not harmful and provide a small amount of nutrition, it's usually a good idea to eat them for the small chance you will be granted an intrinsic.

Variants
SLASH'EM
Main article: Mold (SLASH'EM)
SLASH'EM features two new types of mold: the black mold and the disgusting mold. Their passive attack causes poison damage by way of spores - a nonbreathing character will be unaffected. Mold may also generate on rotting corpses, and mold corpses themselves have a chance to revive, similar to trolls. Also in SLASH'EM, molds may grow on rotting corpses.
Older versions and patches had molds taking on the name of any named corpses they grew on.

SpliceHack
Main article: Moldier
SpliceHack allows fungi to generate on rotting corpses, similar to SLASH'EM. SpliceHack also adds moldiers: humanoid molds that can use weapons and other items.

Encyclopedia entry

Mold, multicellular organism of the division Fungi, typified
by plant bodies composed of a network of cottony filaments.
The colors of molds are due to spores borne on the filaments.
Most molds are saprophytes.  Some species (e.g., penicillium)
are used in making cheese and antibiotics.

[ The Concise Columbia Encyclopedia ] 

References

↑ src/monst.c in NetHack 3.6.6, line 1321