D&D Monster Monday: Gibbering Mouther

D&D Monster Monday Gibbering Mouther

You slowly walk into the damp cave with your sword drawn, unaware of the dangers present in the mound of flesh, eyes, and mouths that lay before you. It slithers towards you, leaving a moist trail of good in its wake. As it gets closer, chattering and chanting the entire way, you feel a crippling fear in the pit of your stomach. You stand there, motionless, as the gibbering mouther spits a glob of blinding liquid at you, blinding you before it quickly begins to feast on your flesh.

For this week I wanted to focus on more of a unique creature as well as one that is on the lower end of the CR spectrum as I have not given that area much focus in this series yet. It’s also about time to come back to the 5e Monster Manual (MM) again as it’s been a few installments of me avoiding it. With that said, the gibbering mouther came to mind immediately when I thought of a unique and low CR creature.

The gibbering mouther is a very unique creature from the MM. It has a very interesting set of abilities and actions that it can take for a creature of CR 2. It has crowd control, breath attacks, swim speed, and a couple of abilities to manage. Of course, this all comes with plenty of limitations.

The gibbering mouther is an aberration so you know it’s going to be freaky as hell. It absolutely lives up to this expectation as it’s a truly disgusting and terrifying creature with some awesome lore and flavor.

Gibbering Mouther Lore

The MM states that its body is an amoeboid form meaning that it’s a big mass of gooey flesh, eyes, and of course, mouths. It can lurch its way across land and through water without any issue. It’s slow, but it will eventually catch up with an unsuspecting victim due to its madness-inducing chattering.

All of the mouths on and in its body constantly babble incoherently since it cannot speak or understand any languages. These are known to drive people and creatures near a gibbering mouther insane. They will either freeze in place or if they’re lucky they’ll run as far away from the creature as possible.

A gibbering mouther is a slow creature, but it has an insatiable hunger for flesh. If its incessant babbling is enough to strike fear into a victim and cause them to freeze it has an eager meal awaiting it. The mouths will quickly gnaw the victim’s flesh off their bones and will eat every part of the creature. Once it’s done, the creature’s eyes and mouth will be absorbed into the gibbering mouther, making it larger and more deadly.

5e Gibbering Mouther Art
The official 5e artwork for the gibbering mouther. Art by Wizards of the Coast.

Gibbering Mouther’s Stats and Abilities

The statblock for the 5e gibbering mouther can be found on pg 157 of the MM.

Base Stats

  • Size: Medium
  • AC: 9
  • HP: 67 (9d8 + 27)
  • Speed: 10 ft., swim 10 ft.
  • STR: 10 (+0)
  • DEX: 8 (-1)
  • CON: 16 (+3)
  • INT: 3 (-4)
  • WIS: 10 (+0)
  • CHA: 6 (-2)

This should be obvious, but the gibbering mouther’s strengths absolutely do not lie in their stats. 9 AC is horrendous, and its only positive ability score is Constitution with a +3 modifier. Everything else is either +0 or negative. While gibbering mouthers have swim speed, it’s only 10 ft. just like their base movement speed. 67 hit points is above average for a CR 2 creature though, so it does have that going for it.

Resistances, Immunities, Saves, and Skills

  • Condition Immunities: prone
  • Senses: darkvision 60 ft., passive Perception 10
  • CR: 2 (450 XP)

The only benefits the gibbering mouther has in this section is darkvision and immunity to the prone condition. While prone is one of the most commonly afflicted conditions in 5e it’s not much of a benefit. It still has very poor Strength, Dexterity, Wisdom, and Charisma modifiers so it is easily afflicted by the other conditions. Having immunity to one condition is great, but that only rules out so much. As a medium creature, it is still able to be grappled by a player as well which restricts what little movement it has.

Abilities and Traits

Aberrant Ground. The ground in a 10-foot radius around the mouther is doughlike difficult terrain. Each creature that starts its turn in that area must succeed on a DC 10 Strength saving throw or have its speed reduced to 0 until the start of its next turn.

Gibbering. The mouther babbles incoherently while it can see any creature and isn’t incapacitated. Each creature that starts its turn within 20 feet of the mouther and can hear the gibbering must succeed on a DC 10 Wisdom saving throw. On a failure, the creature can’t take reactions until the start of its next turn and rolls a d8 to determine what it does during its turn.

1 to 4, the creature does nothing. 5 or 6, the creature takes no action or bonus action and uses all its movement to move in a randomly determined direction. 7 or 8, the creature makes a melee attack against a randomly determined creature within its reach or does nothing if it can’t make such an attack.

Here is where we start to see the payoff for those poor stats. The gibbering mouther has 2 passive traits that affect creatures within 10-20 feet of them. Both of these have the ability to remove their enemies’ maneuverability throughout the battlefield or take away their turn entirely. However, they both have only a DC 10 requirement to pass the save so they are fairly negligible to higher level characters. This is another reason why I believe this is a great creature for low-level PCs rather than one that can scale upwards.


Multiattack.The gibbering mouther makes one bite attack and, if it can, uses its Blinding Spittle.

Bites. Melee Weapon Attack: +2 to hit, reach 5 ft., one creature. Hit: 17 (5d6) piercing damage. If the target is medium or smaller, it must succeed on a DC 10 Strength saving throw or be knocked prone. If the target is killed by this damage, it is absorbed into the monster.

Blinding Spittle (Recharge 5-6). The mouther spits a chemical glob at a point it can see within 15 feet of it. The glob explodes in a blinding flash of light on impact. Each creature within 5 feet of the flash must succeed on a DC 13 Dexterity saving throw or be blinded until the end of the mouther’s next turn.

While the gibbering mouther only has a +2 to hit, it still deals 17.5 piercing damage on average which is a massive hit for a CR 2 creature. Couple this with it potentially knocking a character prone and you have a very solid attack. If a creature dies from the hit they are automatically absorbed by the creature, raising the stakes in this fight a bit higher.

Blinding Spittle is a great ability as it inflicts the blind condition for an entire combat round, this is long enough to give the gibbering mouther advantage on attacks against a blinded target. Plus, these creatures have disadvantage on making attacks helping this squishy mass of low AC to survive a bit longer.

Gibbering Mouther 2e
The official 2e artwork for the gibbering mouther. I love the addition of the hand desperately trying to grab their weapon.

Gibbering Mouther’s Strengths

Passive AoE Crowd Control

Between Aberrant Ground and Gibbering the gibbering mouther has plenty of tools to impose crowd control on their enemies. While both have a DC of 10 they do have a large benefit compared to many other creatures’ CC abilities. Once a creature passes the save they are not immune to the save. As long as they stay within the radii of the abilities they will have to continue making the saves.

Both of these abilities have the potential to either negate a creature’s turn completely or hinder their positioning. Aberrant Ground reduces their speed to 0 until the start of their next turn and Gibbering mechanically does the same or could even force them to move their full movement in a random direction.

All this is done without using any of the gibbering mouther’s action economy too which leaves it able to still use its action to attack the enemy.

Heavy Hitter

The +2 to hit and +0 to damage does hurt the gibbering mouther’s ability to deal damage on its single Bites attack per round. However, when it does hit it hits for 5d6 piercing damage which is an enormous amount of damage for a CR 2 creature. It’s absolutely a high-variance creature in that it could do anywhere from 6 to 30 piercing damage. For reference, this is enough to flat-out kill a level 1 or 2 player.

Its Blinding Spittle attack has a 1/3 chance of recharging each turn which is pretty normal for most recharge attacks in 5e. This attack having a 15 ft. range and 5 ft. radius is also pretty great as it ensures that wherever the spittle lands the gibbering mouther could most-likely reach the creature with its movement. If the gibbering mouther can inflict blindness on an enemy it will help both its hit chance and damage avoidance for an entire round.

Gibbering Mouther’s Weaknesses

Easily Crowd Controlled

While it has immunity to being knocked prone, the gibbering mouther still has mediocre or low Strength, Dexterity, Wisdom, and Charisma which are all fairly common abilities for saving throws. It does have a +3 modifier to Constitution which is one of the most common saving throw abilities, but having poor or mediocre stat allocation in everything else outweighs this positive trait.

Any condition that imposes advantage to hit the gibbering mouther or takes away what little movement it has will be detrimental to the creature. It needs to keep moving towards the enemy in order to afflict them with its Aberrant Ground and Gibbering abilities.

Low AC and Ability Scores

The gibbering mouther does have an above-average amount of HP for a CR 2 creature. However, this doesn’t matter when its AC is 9, is easily crowd controlled, and has no damage resistances or immunities. This makes for a very easy-to-hit creature and it has no way to lessen the damage dealt to it which is never ideal.

This is a recipe for disaster if the party is able to kite the gibbering mouther around the room, or simply stay further than 20 ft. from the creature. They will be able to pelt it easily and not be affected by Blinding Spittle, Gibbering, and Aberrant Ground which removes most of the gibbering mouther’s ability to control the battlefield.

Gibbering Mouther by Prodigy Duck
Its disgusting terror translates well even in a more cartoony art style! Art by ProdigyDuck.

How to Play a Gibbering Mouther

Small Rooms and Difficult Terrain

Designing an encounter where a gibbering mouther has to slog its way across a large room will turn the encounter from an interesting and potentially high-stakes fight to a trivial engagement. You’ll want to design an encounter where the gibbering mouther can reach the party with its Aberrant Ground and Gibbering reliably.

Throwing it into a room where swimming is required or even a room full of difficult terrain is another great idea. It has swim speed and most PCs will not and will have to move through difficult terrain to do so. This drops them down to 10-15 ft. speed which is right on par with the creature. They cannot outrun it in the water.

As far as difficult terrain is concerned, the gibbering mouther would still be affected by it. However, it only reduces its speed from 10 ft. to 5 ft. which in the grand scheme of things is not a huge reduction. The more movement a creature has, the more powerful the effect of difficult terrain has on them.

Keep Lurching Forward

No matter what, the gibbering mouther needs to keep pushing through. It requires sustenance and will spend the rest of its life constantly seeking it. It needs to constantly move towards the enemy and focus in on them. The more enemies it can put inside of its 10-20 ft. radii, the more likely it will be able to feast. It needs to keep lurching forward until it finds a victim it can hit, blind it with its Blinding Spittle and wreak havoc upon it.

It’s a creature with 3 Intelligence, it can’t be played in an extremely tactical manner. All it understands is that it is hungry and there is food in front of it. Its Wisdom is average so it will know enough to try to keep itself out of as much harm as possible, but it won’t necessarily be able to tell what’s a priority target.


The gibbering mouther has a lot of different mechanics in its kit and is a great way to showcase things like a rechargeable weapon attack to new players. However, due to its low AC and horrible mobility, it’s easily taken care of by powerful magic and ranged attacks. Because of this, I feel that they can only be used once against a party and generally in the lower levels.

You would need a group of gibbering mouthers to challenge a medium or high-level party, and they don’t work well against them. High-level characters have much more spells and abilities granting them CC, they have better ability scores for saves, and the gibbering mouthers’ Gibbering and Aberrant Ground would eventually affect each other. They’d be more likely to CC each other than they would the party.

They’re a unique creature with a lot of flavor, and so long as your players can’t kite to their death they can make for an interesting encounter. It’s a creature that has a lot it can do while only having a handful of tools at its disposal.

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