Troglodyte Tuesday: Gibbering Mouthers

n.b. Welcome to Troglodyte Tuesday! A feature in which I present (or re-present) monsters I have created or adapted for use in my own 5E D&D campaigns, including lore, tips for running them, and a stat block. Today we have my own version of the Gibbering Mouther.

Creating the Gibbering Troll made me take a closer look at the Gibbering Mouther, since the former can transform into a huge-sized version and its limbs, if hacked off, turn into the typical kind. Perhaps unsurprisingly, I was unimpressed. I have no problem with the way the 5E emulates the older editions versions (though I remember them being tougher, scarier) but was disappointed in 5E’s refusal to build on the descriptive elements of the monsters with more powers and defenses. So as is my way, I decided to make my own.

Firstly, you’ll notice three different stat blocks below. I made one for each size mentioned in the lore I wrote for the mouthers. While the most common type is Medium-sized as written in the 5E SRD, it seems strange to me that an amorphous monster that absorbs people couldn’t get bigger or fuse with others of its kind. As such, I made Large and Huge versions (though the Huge version came first since Gibbering Trolls can transform into one when they reach the end of their lifecycle). These things are scarier the bigger they get.

More Defenses. These things should be hard to kill and should resist a bunch of common spells and abilities just due to their corrupt and alien nature. So it was easy to make these mindless things impossible to charm. They were already immune to being Prone, since they undulate along the ground, but with no central brain I thought making them immune to being stunned also makes sense. Similarly, their many eyes seems to make blindness something they could safely ignore, given they have so many to spare. Their amorphous and ever changing form also makes them immune to petrification (something that probably comes in handy when running into a Medusa when you have countless eyes). In fact, having gibbering mouthers be the result when the reversal of a petrified creature goes wrong is a cool seed an encounter (or whole adventure) could be built upon. Speaking of being amorphous, it is also this quality in my mind that should make them immune to paralysis, being restrained, and having resistance to bludgeoning damage. Without bones, the best a war hammer can do is burst some eyes and smash some teeth! Lastly, what in the Nine Hells could frighten such a thing? What would a frightened Gibbering Mouther even look like? No, it is best if its supernatural otherness make it exist beyond fear.

As for the immunity to acid, that is almost a throwaway thing. I just imagine a gibbering mouther as slimy and caustic already. Heck, if it did not make it even more complex I might have grappled targets also take round by round acid damage from the thing.

Grappling & Absorption. I didn’t like how, as written, the Gibbering Mouther can absorb creatures, but only those it happens to kill with its bite, rather than engulfing and grappling those creatures with their oozing heft and those many mouths. If these monsters are supposed to emulate a Lovecraftian shoggoth, then let it act like one and let it attempt a free grapple on a successful bite(s) attack and flop over onto the target. These things aren’t very strong, but imagine their dead weight can help them envelope the weak and unlucky. It is this same assumption that made me give the larger versions of the mouther have a better chance at grappling creatures smaller than it is.

Opposed rolls are exciting and build tension. They are a great opportunity to roll in the open even if you are a DM that normally rolls behind a screen. It is for this reason that I use them for opposed skills and struggles between opposing figures trying to do the same thing at the same time or resisting something like a grapple.

Gibbering Mouthers become especially scary when they are trying to absorb dying or otherwise incapacitated targets, automatically causing failed death saves for the former, and very likely doing immense damage that will drop the target to dying with the second (since it is an auto-crit). Furthermore, I wanted absorption to actually help the Gibbering Mouther in some way, so I had it heal the monster some, by incorporating the absorbed flesh into itself. To determine how many hit points the mouther regains, roll the absorbed creatures hit dice and divide the result in half (rounded down). Any hit points beyond the monster’s maximum are kept as temporary hit points that last until lost or until after its next long rest. If a creature has made use of any of its hit dice (such as for a short rest or to activate an ability) before being absorbed, those hit dice are not rolled towards the hit points regained. Remember! Temporary hit points do not stack! So if a Gibbering Mouther absorbs more than one creature during an encounter, it only gains the greater number of hit points, not both.

More Sizes. While I didn’t want Gibbering Mouthers to grow through absorption like the Gibbering Troll does, I did like the idea of two or more of them fusing sometimes to become Large and then Huge Gibbering Mouthers. Could they become Gargantuan? I guess they could, though I did not feel much like making one. For whatever reason I image they would eventually collapse upon themselves if they get beyond a certain size. Could they be Small? Or Tiny? Eh. I guess, but again the aesthetics of it do not appeal to me and I just think they lose their sense of awe and horror when they are that small.

I made some changes between sizes, probably the most obvious being that the bigger ones are easier to hit (lower AC) but move a little faster. The former is easy to understand, but the latter is tied to how I imagine a Gibbering Mouther moving. Yes, they drag themselves along with their mouths, but I imagine also shift their bulk forward and as high as possible to allow momentum and gravity to drag them back down in the direction they want to move. The bigger a mouther is, the more length that represents. Lastly, I made the area of effect of their Aberrant Ground ability a little larger for each bigger size and the loudness of their gibbering effect a greater radius of those unlucky enough to hear it.

​Below you will find descriptions of the creature, a full stat block, and a link to the PDF version of the full description and 5E stat block.

Click here for a PDF version of full description and stat block.

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