Soveliss knelt in the gray mud of the cavern floor and frowned. The tracks were unmistakable: four pairs of broad, segmented feet, each step deeper at the toes than at the heel, followed by the broad wallow of the tail.
“Chuul,” he said softly. His eye fell on a small splatter of blood, a place where the monster’s steps hesitated for a moment before continuing. Likely the creature had paused at this spot to shift the villager from one claw to the other.
Ahead of him a great black lake stretched off into the darkness, cold and still as death itself. Water dripped somewhere in the unseen reaches of the cave, a single drop every ten heartbeats. The chuul’s tracks continued into the icy water.
“The lake?” rumbled Tordek. The dwarf stood with his feet planted wide, eyeing the water with distaste.
“Yes,” said Soveliss. The elf straightened and brushed the mud from his hands. “It went in, but it did not come out. I think it knows that we followed it here.”
“Damn,” said Tordek. He looked at the lake again and shook his head. “I hate the water.”
A horrible mix of a large lobster-like aberration, insect and serpent the Chuul are carnivorous lurkers who partially submerge themselves to surprise their prey. The many tentacles protruding from their mouths are capable of causing paralysis with only a single touch, thus leaving ample opportunity for their powerful claws to strike. These creatures are relics in that they were created during the primeval ages when aboleths ruled a vast empire spanning the oceans of the world. The Chuul survived the crumbling of these empires still carrying the will of their aboleth creators: in collecting humanoids, gathering treasures, amassing magic and consolidating power. Although they were cast adrift with the rise of gods and the end of the aboleth rule these compulsions remained.
Chuul were perfectly obedient creatures created by the aboleths to circumvent their only weakness, being bound to the water. They would collect sentient creatures and magic. By design the Chuul were made to endure the ages of the world, growing in size as the eons passed, commonly reaching 650 pounds and 8ft long. Carrying on this mentality and guarding ruins of the aboleths empire tirelessly, they still linger silently observing these old commands.
Chuul can be found in aquatic lairs in a variety of watery habitats. Although they prefer swamps, jungle lakes, temperate marshes, and underground bodies of water, some individuals would purposely seek out sewer tunnels or coastline shipwrecks in order to provide themselves with a more accessible source of food. They were also known to use rivers, and even oceans, in order to travel to new locales. Chuuls could be found living as solitary creatures, in pairs, or in small groups of 3-5, which were known as pods. A pod would purposely seek out a body of still water that was large enough to support the entire group. Some Chuul, particularly older ones, create lairs by digging up lake bottoms and building rudimentary structures from trees and stones.
Oviparous creatures, adult Chuul produce clusters of slimy yellow-green eggs from which hatchlings emerge. An adult Chuul can lay such egg sacs only rarely, and so would viciously protect them, as would any fellow pod members. If a Chuul with hatchlings found itself in a food-poor environment, it would attempt to collect humanoid prisoners alive and bring them to their hatchlings in the nest. Seemingly counterintuitive to their aforementioned protective care towards their young, Chuuls were known to attach their egg sacs to the underside of ships, boats, and rafts in an attempt to increase their distribution to new lands.
A Chuul lair consisted of circular rooms that are interconnected by tunnels made just large enough for the biggest member of the resident pod to squeeze through. One of the aforementioned rooms would always be a trophy room, as Chuuls were born hoarders. After making a humanoid kill, a Chuul would keep aside something from the victim as a trophy, whether shiny armor, a piece of jewelry, or even a well-crafted saddle. If the victim was not carrying anything of interest, then the Chuul would settle for displaying their skull in their trophy room.
Despite their monstrous appearance, Chuuls are actually more intelligent than they seem, often setting traps and ambushes for their prey. Although they are still far from civilized; lacking any sort of culture, ability to make tools, or settlements. However, they share a racial memory, which they possess from the moment they hatch. This allowed a Chuul to clearly recall events experienced by previous generation, but this became less and less vivid the further back it went.
Chuuls tend to be rather prone to mutations, with magical experimentation, planar rifts, and polluted water affecting and altering them far more easily than other creatures, leading to gigantic and/or poisonous individuals. However, it was only under the experimentation of aberrant magic-users that such mutations reached truly terrifying proportions. Such tinkering was done with the aim of fully unlocking the Chuuls’ psychic potential and thus create formidable minions that were not only physically powerful, but possessed potent mental powers as well. Chuul could find themselves aligned with Mind Flayers if it allowed them to consume more humanoids or further their innate drive to slay explorers. They are also capable of sensing magic at a distance thus proving themselves useful to Mind Flayers.
If a Chuul were to ever come in contact with a aboleth their long standing psychic bonds would immediately cause them to assume their old roles. Such Chuul would redirect their compulsions to the service of the aboleths’ sinister purposes.
Chuul are typically limited to their environment and rely on their ability to impose advanced hunting tactics to ambush their prey. You want to embrace these tactics and show how potent these hunters are. Typically, Chuul will be strong physical combatants who fight by grabbing and piercing their target with their enormous claws. After the unfortunate victim was trapped within the strong grip of a Chuul’s pincer, it was either simply crushed or brought towards the creature’s mouth tentacles, which grasp and exude a paralytic secretion. A Chuul would normally try to always have one claw free during combat, so that it could deal with any other opponents that might try to interfere. If facing a large number of foes, it would drop a paralyzed or dead victim before moving onto the next attacker.
Much like a number of other aberrant creatures, Chuuls can have psychic abilities. However, it is unusual for a young Chuul to have access to such powers, instead they would gradually become able to exude psychic static as they aged. Older and larger creatures are able to emit a psychic moan that weakened resistance to psychic attacks and use a psychic lure to draw victims towards it.
Chuuls are also able to see perfectly well in the dark, are very alert, and have an innate immunity to poisons. They can act as sentries to a Mind Flayer colony, guardians of ancient treasure or ruins containing rich history, or take a more hive mind approach under the servitude of a returning aboleth.
Using their susceptibility to mutations, Chuuls can also become larger foes armed with a number of Psionic abilities under the influence of your BBEG.