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Gibbering Mouther


AC 9

HP 67 (9d8 + 27; bloodied 33)

Speed 20 ft., swim 20 ft.

Proficiency +2; Maneuver DC 10

Damage Resistances psychic

Condition Immunities prone

Senses darkvision 60 ft., passive Perception 10


Amphibious. The mouther can breathe air and water.

Gibbering Mouths. The mouther babbles constantly. A living non-aberration creature that starts its turn within 30 feet and can hear its gibbering makes a DC 10 Intelligence saving throw . On a failure, the creature is confused until the start of its next turn.

Reality Eater. The ground within 15 feet of the mouther is the consistency of sucking mud and is difficult terrain to all creatures except the mouther. Each non-aberrant creature that starts its turn in the area or enters it for the first time on its turn makes a DC 10 Strength saving throw . On a failure, its Speed is reduced to 0 until the start of its next turn.


Multiattack. The mouther makes two bite attacks.

Bite. Melee Weapon Attack: +2 to hit, reach 5 ft., one creature. Hit: 7 (2d6) piercing damage, and the target makes a DC 10 Strength saving throw , falling prone on a failure. If the target is killed by this attack, it is absorbed into the mouther.


Blinding Bile (Recharge 56). Ranged Weapon Attack: +2 to hit, range 20/60 ft., one creature. Hit: 3 (1d6) acid damage, and the target is blinded until the end of the mouther’s next turn.


The gibbering mouther moves towards the closest creature and bites it. If possible, it spits bile at a creature right before it bites. If its blinding bile attack is charged and no creatures are near enough to bite, it uses it on whichever creature attacked it most recently. The mouther is not above biting unconscious opponents, and it does not retreat.

Legends and Lore

With an Arcana or Religion check, characters can learn the following:

DC 10 Although none know for certain, many scholars believe gibbering mouthers are horrible abominations from another reality.

DC 15 A gibbering mouther’s babble can drive even the strong-willed mad.

DC 20 The presence of a gibbering mouther warps reality itself, transforming the ground around it into a sucking mire.


The debate within magical circles rages whether these foul aberrations were created by reckless sorceries, or if they slipped into the world from some mad, alternate reality. The result is the same: a horrible mass of mouths and eyes, and a maddening gibber the ear strives vainly to understand, even as all other senses react in horror.

Aberrant Body. Gibbering mouthers are not only amorphous, but they actually warp the terrain around them into a soft, glue-like consistency. In areas frequented by gibbering mouthers, reality itself grows tenuous; planar rifts may open to other realms, and laws of nature such as gravity may behave unpredictably.

Gibbering mouthers use their many mouths to pull themselves over solid ground or through water with equal ease. Each time a gibbering mouther consumes a victim, it adds the creature’s mouth and eyes to its appalling mass.

A Meaning In The Madness? Each of the mouther’s voices speaks its own unique utterances, from sibilant whispers to ear-splitting wails. This babble is utterly incoherent but can have dire effects on a listener’s sanity. Nonetheless, some scholars have become convinced that if these ravings could be deciphered, they would reveal knowledge previously unknown to mortal minds. This might be true, or it may be a delusion caused by contact with gibbering mouthers. Those who have attempted to solve this riddle have either never returned...or returned mad and gibbering themselves.


1 Attacks on sight

2 Attacks on sight while shouting, "No," "Don't hurt me," "Glad to meet you," and other non sequiturs

3 Focused on warping its environment (perhaps making a new tunnel or sculpting a copy of itself); only attacks if you approach or interfere

4 Acting nonsensically: talking to objects, trying to climb up walls, etc.


1 Distant babbling voices

2 Rocks and other solid objects are warped or crumbling

3 A random character gets a sudden headache, or telepathically overhears babbling voices

4 A mouth appears on a solid object, yells a few words, and vanishes


Gibbering mouthers appear in laboratories, eldritch dungeons, and places where the walls of reality are thin.

CR 0–2 gibbering mouther

CR 3–4 2 gibbering mouthers ; gibbering mouther with grick or mimic

CR 11–16 murmuring worm

Monster Type Description

Aberrations are unnatural beings that don’t belong to this plane of existence. Many aberrations are telepathic and use a mental power known as psionic power instead of magic. An aboleth is an aberration.