Dungeon Master's tool for madness-inducing voices
Homebrew version of the Monster Manual original. The creature telepathically knows the characters' names, and names one victim from its hundred mouths, driving the party into a killing frenzy!
Large Aberration, Chaotic Evil
Armor Class 18 (Psychic Distortion)
Hit Points 100 (12d10 + 36)
Speed 10 ft.
Saving Throws Int +9, Wis +8, Cha +9
Skills Deception +9, Perception +8, Insight +8
Condition Immunities Charmed, Frightened, Prone
Senses Darkvision 60 ft., Passive Perception 18
Languages Telepathy 120 ft. (All languages known by creatures within range)
Challenge 12 (8,400 XP)
Reactive Mirror. Any creature that hits the Gibbering Mouther with a melee attack must succeed on a DC 16 Intelligence saving throw or take psychic damage equal to half the damage dealt to the creature.
Amorphous. The Gibbering Mouther can move through a space as narrow as 1 inch wide without squeezing.
Chorus of Condemnation. The hundreds of mouths on the Gibbering Mouther begin chanting the name of one character it can see within 60 feet (the Pariah). Every other character within 60 feet that can hear the chant must make a DC 15 Intelligence saving throw.
On a Failure: The character is compelled by a psychic "logic virus". It must use its turn to move toward the Pariah and take the Multiattack or Cast a Spell action to deal maximum damage to the Pariah. The character can attempt the saving throw again at the end of its next turn.
On a Success: The character is unaffected but takes 2d10 psychic damage from the mental strain.
The effect lasts until the Gibbering Mouther is silenced or killed. The Gibbering Mouther may attempt this action every turn.
Psychic Sob The creature lets out a collective, multi-voiced wail of pure grief. Each character within 30 feet must make a DC 18 Wisdom saving throw, taking 35 (10d6) psychic damage on a failed save, or half as much on a successful one. If a character fails this save while currently affected by the Chorus of Condemnation, they also fall Prone as they are overwhelmed by the Pariah's "sins."