| Climate/Terrain: | Any/swamp, underground |  |
| Frequency: | Very rare | |
| Organization: | Solitary | |
| Activity Cycle: | Diurnal | |
| Diet: | Omnivore | |
| Intelligence: | Semi (2-4) | |
| Treasure: | Q | |
| Alignment: | Neutral | |
| No. Appearing: | 1 | |
| Armor Class: | 1 | |
| Movement: | 3, Sw 6 | |
| Hit Dice: | 4+3 | |
| THAC0: | 17 | |
| No. of Attacks: | 6+ | |
| Damage/Attack: | 1(x6)+1/round | |
| Special Attacks: | Spit, babble, bite | |
| Special Defenses: | Ground control | |
| Magic Resistance: | Nil | |
| Size: | M | |
| Morale: | Very steady (13-14) | |
| XP Value: | 4 HD: 650 8 HD: 3,000 |
The gibbering mouther is an amoeboid form of life composed entirely of mouths and eyes. Its favorite tactic is to lie in wait with its eyes and mouths closed so that it appears to be a lump of earthy material, hoping to surprise creatures stumbling across it. Its only motive is to eat whatever is edible within reach, regardless of whether the food is animal, vegetable, or mineral.
Gibbering mouthers prefer to inhabit swampy or underground regions. They propel themselves by oozing forward, fastening several mouths to the ground and pulling themselves along. A mouther may move faster over fluid and viscous terrains, such as mud and quicksand, by swimming through the muck. Given time, mouthers alter the ground with their special ground control talent to allow this faster form of movement.
Combat: The brain of a mouther is located in its midportion, and its gelatinous body makes it difficult to strike this spot. The mutable nature of the monster gives it a high Armor Class.
The mouther attacks in three ways: babbling, spitting, and biting.
When any edible object is sighted by a mouther, it may begin an incoherent
gibbering that causes confusion (as per the spell) to all within a 60-foot
radius unless a saving throw vs. spell is made. For each round that the
gibbering is heard, those within range must roll another saving throw. Roll
1d8 for each confused character or being:
1 - wanders aimlessly for one round,
2-5 - stands stunned for one round,
6-7 - attacks the nearest living creature for one round,
8 - runs away in fear for two rounds.
The spittle of a gibbering mouther will hurst into a bright flare if it strikes any hard surface. The resulting flash will blind characters looking at it if they fail to make a saving throw vs. petrification. The blindness lasts 1-3 rounds. The mouther may attempt to bite blinded opponents with a +2 bonus to its attack rolls. Blinded victims make attack rolls with a -4 penalty.
A mouther's best attack comes from reaching out and biting with six mouths per round. Each mouth that hits on a die roll of 2 more than needed to hit attaches to the victim and drains an additional 1 hit point per round while attached; the next round, six new mouths attack the victim. When 3 or more mouths are attached to a single victim, that character must make a Dexterity ability check each round thereafter or slip. A felled roll indicates the character has fallen. The gibbering mouther will flow over the victim and bite with 12 more mouths, gaining a +4 bonus to strike its prone and held opponent. If given the opportunity, once it has pulled down one victim, a mouther will try to trap other prey.
When victims reach 0 hit points, they are absorbed into the mouther, giving it another mouth and pair of eyes per victim. Each time a victim is absorbed, the mouther also gains 1 hit point permanently, up to the maximum for its HD. Only living flesh can be absorbed like this - dead, unliving, or undead creatures are not affected.
A mouther always liquefies the ground and stone within a 5-foot radius of itself and can control the consistency of this material by changing it to doughy, tarry quicksand. It requires 30 seconds to alter earth to quicksand, and a full round to mutate stone to earth.
Habitat/Society: Like other amoehoid life forms, gibbering mouthers reproduce by asexual fission. When a mouther has absorbed enough victims to gain its maximum hit points, it splits into two mouthers. Each mouther is a 4+3 HD monster; one has 17 hit points, the other 18 hit points. Because this process takes about four hours, the mouther usually retreats to some small dark den before the fission begins. When the two new mouthers recover at the end of the dividing process, which takes 7+3dl2 turns, each seeks its own new territory.
Gibbering mouthers not only avoid each other's hunting territories, they avoid all physical contact with one another and never fight one another over territory or food. It is believed that bringing two mouthers in physical contact forces them to merge, creating a larger creature with twice the size, HD, and number of attacks, but half the already slow movement of the parent monsters. These great beasts strip the land of anything edible so quickly that they generally die of starvation as soon as prey becomes scarce.
Ecology: Gibbering mouthers are unnatural creatures, usually created by foul sorcery and kept as guards by mages or obscene cults. Although they can survive in the wild, they are more scavengers than hunters, and rarely establish reproducing populations in any but the lushest swamps.