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Malignant Mouth

Medium monstrosity, chaotic neutral

Armor Class 16 (natural armor)
Hit Points 20 (4d8+2)
Speed 0 ft.

12 (0) 6 (-2) 9 (0) 16 (-1) 14 (-1) 14 (+2)

Damage Resistances necrotic, poison
Condition Immunities charmed, frightened
Skills Performance +8
Senses tremorsense 120 ft., passive Perception 12
Languages all
Challenge 3 (700 XP)

Special Traits

  • Magic Resistance. The malignant mouth has advantage on saving throws against spells and other magical effects.


  • Bite. Melee Weapon Attack: +3 to hit, range 5 ft., one target. Hit: 9 (2d8) slashing damage.
  • Focused Shout. Ranged Weapon Attack: +6 to hit, range 60/120 ft., one target. Hit: 7 (2d6) force damage.
  • Cackle (Recharge 5-6). All creatures within a 30 ft.-radius from mouth have one of the following effects. Roll 1d6 separately for each target.
d6 Effect
1 Confusion. Target must succeed on a DC 14 Wisdom saving throw or move in a random direction each turn, making a melee attack against the first target it encounters for 1d6 rounds.
2 Fear. Target must succeed on a DC 14 Wisdom saving throw or drop what it is holding and use its action and move to dash away from the mouth. The target can attempt a new saving throw at the end of each of its turns, ending the effect on a success.
3 Sleep. If the target has less than 5d8 hit points, it falls asleep as per the sleep spell.
4 Cure Wounds. The target is healed for 1d8+2 hit points.
5 Vomit. The target must succeed on a DC 14 Dexterity saving throw or be immobilized for 2d4 rounds. On a successful saving throw, the target moves at half speed for 1d4 rounds.
6 Tongue Lash. Ranged Weapon Attack: +8 to hit, range 10/20 ft., one creature. Hit: the target is pulled next to the malignant mouth, which can then make a bite attack against it with advantage.


This long-forgotten magic mouth has been driven insane and twisted by its exposure to dark magic and the intense loneliness it has experienced.

Magic mouth spells are used to transmit welcomes, warnings, and messages to visitors. As these magical manifestations exist until they are dispelled, some are very ancient and forgotten. On rare occasions, long after the original spellcaster has died, the mouth gains sentience, becoming self-aware. Aware of its predicament and angry over being forgotten, it becomes vicious and utterly demented-a malignant mouth is born. Malignant mouths are usually found in ancient subterranean vaults, forgotten towers, and abandoned scriptoria (places of loneliness surrounded by ages of dark influences).

A malignant mouth remains partially bound by the spell which created it; thus, a malignant mouth will still be triggered to perform its intended duty. It will appear on a wall, object, or statue and delivers the message as intended, except the message is spoken in a twisted, tortured drawl or frenetic shriek. This disquieting noise will be punctuated by insane and painfully loud laughter.

Section 15: Copyright Notice

Tome of Horrors © 2018, Frog God Games, LLC; Authors: Kevin Baase, Erica Balsley, John “Pexx” Barnhouse, Christopher Bishop, Casey Christofferson, Jim Collura, Andrea Costantini, Jayson ‘Rocky' Gardner, Zach Glazar, Meghan Greene, Scott Greene, Lance Hawvermale, Travis Hawvermale, Ian S. Johnston, Bill Kenower, Patrick Lawinger, Rhiannon Louve, Ian McGarty, Edwin Nagy, James Patterson, Nathan Paul, Patrick N. Pilgrim, Clark Peterson, Anthony Pryor, Greg Ragland, Robert Schwalb, G. Scott Swift, Greg A. Vaughan, and Bill Webb

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