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 a troll variation I created for my remix of “The Wayward Wood” (from Dungeon Magazine #30).
I don’t really remember how I came up with the idea of the Gibbering Troll.
I was preparing “The Wayward Wood” an adventure from Dungeon Magazine #32 (November/December 1991) and wanted the troll chieftess to have a servant guarding a place where she kept her treasure. I thought it’d be interesting to have it be her son and reinforce the lack of strong familial affection in troll culture by making him an actual monster, building on the mutagenic qualities of troll-kin.
It was around that time that I was also browsing Gnomish Bazaar looking for more trolls to add to my miniature collection for running that troll-heavy adventure and I happened to spot a picture of something called a Dire Troll. I don’t know what a Dire Troll is or where the stats for one might be found, but the general look fit my conception of a mutated and constantly mutating troll, so I ordered one and painted it. It became Gluklux, the Gibbering Troll.

When I say this thing is a monster, I mean it both figuratively and literally. I ranked it as CR 9, but to be honest, using a CR calculator I found online I came up with CR 11, but that seemed too high, as I think a group of 11th level adventurers would not have too hard a time against one. I guess it would depend on the group’s access to ranged fire or acid magic. CR 9 seemed like a better fit, but your mileage may vary. While this version is slightly more powerful than the one I’d end up running, it was still a challenge for the PCs in my group. They encountered it on an old stone bridge that was was only 25 feet wide, over a subterranean river infested with otyughs, and that had adolescent basilisks living among the rocks that had gathered along the bridge over the centuries. In other words, it was hard to bypass the area without encountering the troll, given the other nearby dangers. Oh, and the party consisted of four 6th level characters, so of course it was a challenge.
It was the presence of basilisks that made me make the Gibbering Troll immune to petrification, but I also thought its constantly changing form made it resist spells or effects that sought to change that form permanently.
As for its chopped off limbs turning into Gibbering Mouthers, I am not sure where the heck that came from. I guess, I was just trying to think of some variations of what happens when a troll has an arm or leg chopped off. And since this abomination has significantly more limbs to chop than the common troll, I liked the idea of them turning into mind-bending mutant monsters as the troll itself simply grows new ones. And then like the Blob, it absorbs what it kills and becomes bigger.
I think of a Gibbering Troll as something close to the D&D equivalent of a bomb, a biological weapon that could destroy a large portion of a town or city if set loose, getting bigger and bigger and harder to kill all the time, and unlike the monster in the blob, it has no special vulnerability to cold. If it absorbs enough flesh to reach 27 hit dice and grow to gargantuan size, it becomes a literal bomb and explodes into a dozen or more gibbering mouthers.
If you want to increase its CR and damage output as its size increases, I encourage coming up with your own methods to track such an increase. However, while I may not have included the details of this in the stat block to keep it from getting too cluttered, I do have a rule of thumb I use for my own purposes. For every hit die increase the Gibbering Troll gets from absorption, I would increase its height by 2 feet (so it is 34 feet tall by the time it reaches Gargantuan size and explodes). Furthermore, I’d increase its CR by 1 for every 3 HD it gains, and increase the base damage dice for its physical attacks by one step each of these times as well. So its claw attacks would go from 2d6+5 to 2d8+5, 2d10+5, and finally 2d12+5, its bite attack would go from 1d8+5 to 1d10+5 to 1d12+5, and finally 2d8+5. Its Head Hunt attack would increase to 2d10+5, 2d12+5 and 4d8+5, and the crushing damage it does as part of a grapple increases to 4d8+5, 4d10+5, and 4d12+5.
This may be a big messy monster, but a solo monster can afford to have some wonky powers and abilities, since you will not have many other monsters to run along with it (at least until it starts slaking off gibbering mouthers).
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.