Gibbering Mouther – DM’s Pocket Guide
Welcome to DM’s Pocket Guide, where we discuss the rules, spells, and monsters of Dungeons and Dragons, 5th edition.
Tricia: Today we are going to talk about the Gibbering Mouther.
Rachel: *gibbering mouth sounds*
T: They are on page 157 of the Monster Manual. And I just recently had to fight one of these that you ran.
R: Yes, you did.
T: It was terrible. I hated it.
R: I think you enjoyed the challenge.
T: I did. It was a very good monster. These things are terrifying.
R: Oh yes.
T: They are aberrations, which means they are come from aliens. It is an amorphous amoeba, medium size, just horror, full of mouths and eyes of its prey, and it’s coming to add you to its form.
R: Yeah. So it’s in the book, it refers to it being created by foul sorcery, like a collection of everything that it’s consumed before and these things are terrifying. I’ve used them twice in games and loved it both times. These things are surprisingly tough and such a great visceral monster to throw at your players. Everybody remembers an encounter with a Gibbering Mouther for sure.
T: Yes. Also can we just pause: Gibbering Mouther is a great name.
R: It’s very descriptive, it’s exactly what it does. For me, it gives me like an idea of like how this thing sounds as it’s coming towards you and kind of what it looks like.
T: Yeah definitely. So as we look at its stat block, I think the thing that stands out to me, first of all, is that it looks kind of easy on the surface. It’s only got 9 armor class, so you’re pretty much gonna hit it no matter what. It’s got 67 hit points and it’s got a speed of 10 feet. So it’s moving very slowly.
R: Oh yeah, this thing doesn’t look terrifying. But with 67 hit points, you won’t kill this thing in one go, and that’s really where this thing gets its foot in the door. If it had feet.
T: Gets its slobbering, massive appendage through the door.
R: I think somewhere is this: it uses the mouths on the bottom to move.
T: That is horrifying. Imagine being the person who was absorbed and your job is to like scrape your teeth along the ground to move it. So, yeah, this thing operates by driving you insane, and I can tell it’s going to do that to us just describing what it does.
R: Yeah, for sure.
T: So some other very basic things. You can’t knock it prone. It does have dark vision. It does have pretty bad passive perception of 10, so if you happen to see it before it saw you, you might be able to sneak past. And then we get into some of its very, very interesting descriptions.
R: Yes, speaking of sneaking past this thing, one of the things that stands out to me when I was reading through this is the mouths of madness or the gibbering effects that it has. It babbles incoherently when it can see any creature that isn’t incapacitated. So if one of my players triggers this thing, I like to, to start with, just like a little, *quiet gibbering sound ending in a low growl*. Wait, that wasn’t me. That was Pepe, the dog we’re looking after right now. Yeah, so starting off with these very small sounds and then joining in with all of the other voices. The way these are described like deep or shrill voices or wailing or undulating or crying out in agony, like imagine the last moments of all of these people who have been absorbed into this thing – what they might be yelling, what they might be thinking about in those last final moments and all those coming out.
T: That’s terrifying. That’s a good way to kickstart initiative, and that would be using the gibbering… it’s not an action, that’s just a thing it can do and it’s fabulous. I love that so much.
R: Yeah. And so the action is the Mouther babbles incoherently when it can see any creature that isn’t incapacitated. Each creature that starts its turn within 20 feet of the Mouther and can hear it – so if you’ve been affected by the deafened condition, you’re immune to this, or if you can’t hear for some reason, you’d be okay – but if you can hear, you have to succeed on a wisdom saving throw. And if you fail, there’s a number of things that can happen to you, and you can’t take reactions until the start of your next turn. And when it is your turn, you’re gonna roll the D8 to decide what happens.
T: Well, when it is your turn is when this is happening, all of this takes place on your turn.
R: Yes, that’s right. It’s an effect that happens to you on your turn.
R: I like to use this as like a surprise round for the Gibbering Mouther as you start to hear these voices, and then any player within 20 feet makes this save and then we get into the initiative. Usually with at least one or two of them having been affected by this.
R: So the the effect of the Gibbering is either a fight, flight or freeze response. So on a 1-4, you’re going to freeze. You’re just not going to do anything.
R: On a 5 or 6, the creature takes no action or bonus action and uses all of its movement to move in a randomly determined direction. So you might even end up running straight into this thing.
T: So this is the flight.
R: Exactly. Yeah. And then on a 7 or 8, you make a melee attack against a randomly determined creature within reach or do nothing if you can’t reach anyone.
T: So, if you are next to your compatriots and you suddenly hear these voices of madness, you’re either gonna fight, which could mean just lashing out wildly and hitting the Gibbering Mouther or you’re going to flight and just try to get away from it but just totally randomly or you’re going to freeze and just do nothing, yeah, love it.
R: And this feeds quite nicely into Aberrant Ground, particularly that one about moving closer to the Mouther. If you’re within 10 foot of this creature, the terrain around it becomes a dough-like difficult terrain and each creature that starts its turn in that area must succeed on a strength saving throw or have its speed reduced to zero at the start of its next turn. So on your first turn this thing might have driven you insane and made you run towards it, and then on your next turn, you are now in this Aberrant Ground and you fail that strength saving throw, you are stuck there and then it’s gonna be the creature’s turn.
R: And well, it can move 10 feet.
T: It’s gonna get you.
R: It can then start to use its actions we haven’t even talked about – the actions that this thing can do on its turn.
T: So it makes a multi-attack. It can do both one bite and one blinding spittle. On a bite, it’s just +2 to hit but it does massive damage if it does hit: 17 piercing damage. But additionally, the creature that its biting has to make a strength saving throw or be knocked prone. If this happens to kill a creature, it is absorbed into the Mouther which is basically, you’re just dead. You’re just dead dead.
R: Mmm, I’ll read this lovely passage: a Gibbering Mouther leaves nothing of its prey behind. However, even as the last of its victim’s body is consumed, its eyes and mouth boil to the surface, ready to join the chorus of tormented gibbering that welcomes the monster’s next meal.
T: Cool, cool. And if that’s not bad enough, it has blinding spittle, which it can glob at a point 15 feet away from it or within 15 feet. And this explodes in a blinding flash of light which is weird, but I like that. And then anything that has been hit by this within five feet of the blinding flash has to make a dexterity saving throw or be blinded until the end of the Mouther’s next turn.
R: Okay, so if you are okay with potentially permakilling one of your players, go look at Gibbering Mouther on page 157 of the Monster Manual.
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