Gibbering Mouther — Many-Mouthed Horror of the Deep
A crawling mass of mouths and eyes whose endless babble breaks concentration, distorts the ground and turns close combat into a feeding frenzy.
The gibbering mouther is a shapeless aberration covered in transient eyes and mouths. It does not stalk prey with stealth or strategy so much as make the ground, sound and space around it increasingly unsafe. Its constant babble confuses nearby creatures, its spittle blinds at range, and its amorphous body can engulf anything that gets too close.
At a Glance
Run It Tonight
Put the mouther somewhere movement already matters: a narrow cavern, flooded drain, broken staircase or room with unstable footing. Its gibbering should start before the party sees the body. Once combat begins, the mouther turns the floor around itself into a trap, spits at anyone trying to stay safely at range and absorbs whichever target falls or becomes isolated.
Rules by Edition
Gibbering Mouther
Medium Aberration, Chaotic Neutral
AC 9; Initiative −1 (9)
HP 52 (7d8 + 21)
Speed 20 ft., Swim 20 ft.
10 (+0)
8 (−1)
16 (+3)
3 (−4)
10 (+0)
6 (−2)
Immunities Prone
Senses Darkvision 60 ft.; Passive Perception 10
Languages None
CR 2 (450 XP); PB +2
Traits
Aberrant Ground. The ground in a 10-foot Emanation originating from the mouther is Difficult Terrain.
Gibbering. The mouther babbles continuously while it does not have the Incapacitated condition. A creature that starts its turn within 20 feet makes a DC 10 Wisdom saving throw. On a failure, roll 1d8: on 1–4 it does nothing; on 5–6 it takes no action or Bonus Action and moves in a random direction; on 7–8 it makes a melee attack against a random creature within reach or does nothing if it cannot.
Actions
Bite. Melee Attack Roll: +2, reach 5 ft. Hit: 7 (2d6) Piercing damage. A Medium or smaller creature has the Prone condition. If the attack reduces the target to 0 Hit Points, the body is absorbed into the mouther and only equipment remains.
Blinding Spittle (Recharge 5–6). Dexterity Saving Throw: DC 10, each creature in a 10-foot-radius Sphere centred on a point within 30 feet. Failure: 7 (2d6) Radiant damage, and the creature has the Blinded condition until the end of the mouther’s next turn.
Gibbering Mouther
Medium aberration, neutral
Armor Class 9
Hit Points 67 (9d8 + 27)
Speed 10 ft., swim 10 ft.
10 (+0)
8 (−1)
16 (+3)
3 (−4)
10 (+0)
6 (−2)
Condition Immunities prone
Senses darkvision 60 ft., passive Perception 10
Languages —
Challenge 2 (450 XP)
Traits
Aberrant Ground. Ground within 10 feet of the mouther is doughlike difficult terrain. A creature starting there must succeed on a DC 10 Strength saving throw or have its speed reduced to 0 until the start of its next turn.
Gibbering. A creature starting its turn within 20 feet that can hear the mouther must succeed on a DC 10 Wisdom saving throw. On a failure, it loses reactions and rolls 1d8: 1–4 does nothing; 5–6 moves randomly without taking an action or bonus action; 7–8 attacks a random creature within reach if possible.
Actions
Multiattack. The mouther makes one Bites attack and uses Blinding Spittle if available.
Bites. Melee Weapon Attack: +2 to hit, reach 5 ft., one creature. Hit: 17 (5d6) piercing damage. A Medium or smaller creature must succeed on a DC 10 Strength saving throw or be knocked prone. A creature killed by this attack is absorbed into the mouther.
Blinding Spittle (Recharge 5–6). The mouther targets a point within 15 feet. Each creature within 5 feet of that point must succeed on a DC 13 Dexterity saving throw or be blinded until the end of the mouther’s next turn.
Gibbering Mouther CR 5
XP 1,600
N Medium aberration
Init +3; Senses all-around vision, darkvision 60 ft.; Perception +12
Defense
AC 19, touch 13, flat-footed 16 (+3 Dex, +6 natural)
hp 46 (4d8+28)
Fort +8, Ref +4, Will +5
Defensive Abilities amorphous; DR 5/bludgeoning; Immune critical hits, precision damage
Offense
Speed 10 ft., swim 20 ft.
Melee 6 bites +7 (1d4 plus grab)
Special Attacks blood drain, engulf (6d4 damage plus 2 Con damage, AC 13, hp 4), gibbering, ground manipulation, spittle (+6 ranged touch)
Statistics
Str 10, Dex 17, Con 24, Int 4, Wis 13, Cha 12
Base Atk +3; CMB +3 (+7 grapple); CMD 16 (can’t be tripped)
Feats Weapon Finesse, Weapon Focus (bite)
Skills Perception +12, Swim +8; Racial Modifiers +4 Perception
Language Aklo
Special Abilities
All-Around Vision (Ex). The mouther sees in every direction and cannot be flanked.
Amorphous (Ex). It is immune to critical hits and precision damage and can squeeze through unusually narrow spaces.
Blood Drain (Ex). While maintaining a grapple after grabbing, attached mouths deal 1d4 bite damage and 1 Constitution damage each round.
Engulf (Ex). The mouther can engulf one creature of its size or smaller. The victim remains trapped inside the body while mouths continue feeding.
Gibbering (Su). Creatures within 60 feet must succeed on a DC 13 Will save or be confused for 1 round. A creature that saves is immune to that mouther’s gibbering for 24 hours.
Ground Manipulation (Su). As a standard action, the mouther softens nearby stone or earth into muddy difficult terrain for 1 minute.
Spittle (Ex). Each round the mouther can spit acid at one target within 30 feet. On a hit the target must succeed on a DC 18 Fortitude save or be blinded for 1d4 rounds.
Ecology
Environment any underground
Organization solitary
Treasure standard
Gibbering Mouther
Medium Aberration
Hit Dice 4d8+24 (42 hp)
Initiative +1
Speed 10 ft. (2 squares), swim 20 ft.
Armor Class 19 (+1 Dex, +8 natural), touch 11, flat-footed 18
Base Attack/Grapple +3/+3
Attack bite +4 melee (1) or spittle +4 ranged touch (1d4 acid plus blindness)
Full Attack 6 bites +4 melee (1) and spittle +4 ranged touch (1d4 acid plus blindness)
Space/Reach 5 ft./5 ft.
Special Attacks gibbering, spittle, improved grab, blood drain, swallow whole, ground manipulation
Special Qualities amorphous, DR 5/bludgeoning, darkvision 60 ft.
Saves Fort +7, Ref +4, Will +5
Abilities Str 10, Dex 13, Con 22, Int 4, Wis 13, Cha 13
Skills Listen +4, Spot +9, Swim +8
Feats Lightning Reflexes, Weapon Finesse
Environment underground
Organization solitary
Challenge Rating 5
Treasure none
Alignment usually neutral
Gibbering (Su)
All creatures other than mouthers within 60 feet must succeed on a DC 13 Will save or be affected as though by confusion for 1d2 rounds. A successful save grants immunity to that mouther’s gibbering for 24 hours.
Spittle (Ex)
As a free action each round, the mouther can make a ranged touch attack against one target within 30 feet. On a hit it deals 1d4 acid damage; a DC 18 Fortitude save prevents blindness for 1d4 rounds.
Blood Drain and Swallow Whole (Ex)
A creature engulfed in the mouther’s amorphous body automatically takes 1d4 Constitution damage each round until it escapes.
Ground Manipulation (Su)
The mouther can soften adjacent stone and earth into a quicksand-like morass, making the ground dangerous to other creatures.
Behaviour
Gibbering mouthers do not form societies or organise territory. They drift toward food, moisture and places where prey is forced to move close. Their alien voices are not conversation in the ordinary sense; a mouther may repeat fragments of absorbed speech without understanding them as another creature would.
The creature is not automatically malicious. It is simply disastrously hungry and difficult to approach without becoming part of it.
Signs Before Initiative
- Several voices seem to be arguing from behind a wall, but none pauses long enough to answer.
- The floor becomes soft or rubbery near one section of a cavern.
- Acid spots appear on stone at face height around a low tunnel.
- Blood trails end without a body or obvious drag marks.
- Eyes appear briefly in puddles or fleshy residue, then disappear.
- Scattered equipment remains while bodies are completely missing.
If Violence Starts
The mouther wants creatures nearby. It advances through terrain that slows everyone else, spits at ranged attackers and lets its gibbering disrupt anyone trying to coordinate. In the older editions, once it grabs something it should immediately begin the engulf and blood-drain sequence rather than trading ordinary bite damage.
Counterplay
Distance is the safest answer. The creature is slow in every edition, even though the 2024 version is faster than its predecessor. Ranged attacks and terrain that the mouther cannot easily soften keep characters away from its mouths.
Silencing or blocking the gibbering helps in editions where hearing is required. Blinding protection matters against its spittle, and bludgeoning weapons are especially valuable against the older damage-reduction version.
Origins
There is no need to give every gibbering mouther the same origin. Some may be spontaneous aberrant life, some the product of failed magic, and some fragments of larger alien organisms. What matters at the table is that the standard mouther is its own creature, not automatically a lesser shoggoth or a Fateforge Canker guardian.
Using a Gibbering Mouther in an Encounter
The voices below. Miners hear several missing workers calling from a sealed lower tunnel. The voices overlap and repeat the same broken phrases.
The soft floor. A dungeon corridor turns increasingly spongy underfoot before the party can see what is changing it.
The missing bodies. A battlefield contains weapons, armour and blood but almost no corpses.
The sewer junction. The mouther occupies the one intersection every patrol must cross, and the city assumes the disappearances are criminal.
Related Creatures
Browse the Aberration Bestiary, or compare other amorphous horrors such as the Black Pudding. The distinction matters: a gibbering mouther is an aberration with perception, gibbering and mouths, not merely an ooze with eyes.
Rules Sources and Licensing
The 5.5e/2024 Gibbering Mouther is from SRD 5.2.1, released under Creative Commons Attribution 4.0 International. The 5e/2014 creature is from SRD 5.1, also available under CC BY 4.0.
The Pathfinder 1e statistics derive from the open Pathfinder Roleplaying Game Bestiary. The D&D 3.5e statistics are Open Game Content from the Revised d20 System Reference Document. The former Fateforge Canker variant has been removed from the default rules presentation rather than conflated with the standard monster.