This giant translucent leech has three squirming tentacles around an orifice on one end and a stinger on the other.

Hyaleth CR 10

XP 9,600
N Large aberration (aquatic)
Init +6; Senses darkvision 60 ft., thoughtsense 60 ft.; Perception +20


AC AC 23, touch 12, flat-footed 20 (+2 Dex, +1 dodge, +11 natural, –1 size)
hp 127 (15d8+60)
Fort +11, Ref +7, Will +11
DR 10/slashing; Immune acid; Resist cold 10


Speed 20 ft., burrow 20 ft. (wet earth or saturated stone only), swim 30 ft.; aquiferous glide
Melee sting +16 (1d8+5 plus poison and probe intellect), 3 tentacles +14 (1d6+2 plus grab)
Space 10 ft.; Reach 10 ft.
Special Attacks adaptive digestion, engulf (DC 22), poison


Str 21, Dex 15, Con 18, Int 12, Wis 14, Cha 11
Base Atk +11; CMB +17 (+21 grapple); CMD 30 (can’t be tripped)
Feats Combat Reflexes, Dodge, Great Fortitude, Improved Initiative, Multiattack, Skill Focus (Stealth), Weapon Focus (sting, tentacle)
Skills Escape Artist +20, Perception +20, Stealth +22 (+26 when swimming), Survival +20, Swim +31; Racial Modifiers +4 Stealth when swimming
Languages Aklo, Common; telepathy 100 ft.
SQ compression


Adaptive Digestion (Ex)

A hyaleth can alter the makeup of its digestive secretions to suit one of two different purposes. It can switch between secretions as a swift action, and each secretion has a different effect on creatures the hyaleth has engulfed with its engulf extraordinary ability. The hyaleth can choose one of the following effects, and it must apply the same effect to all creatures it has engulfed. A hyaleth can affect engulfed creatures with only one of the following effects per round.

  • Digest Body: Engulfed creatures take 2d6 points of acid damage and must succeed at a DC 21 Fortitude save or take 1d2 points of Constitution damage. A creature reduced to negative hit points by this effect is dissolved entirely.
  • Digest Thoughts: Engulfed creatures that are awake must succeed at a DC 21 Will save or take 1d2 points of Intelligence damage and fall asleep for 1 hour. Each time a creature fails its save against this effect, as a free action the hyaleth can retrieve one answer to a specific question as though sifting through the creature’s surface thoughts with detect thoughts. Alternatively, the hyaleth can attempt one Knowledge check in a skill in which the engulfed creature has at least 1 rank, using the creature’s current total skill modifier. This is a mind-affecting effect. The secretions used to digest thoughts are foamy and oxygenated, allowing engulfed creatures to breathe normally while it is in effect.

The save DCs are Constitution-based.

Aquiferous Glide (Su)

A hyaleth can travel through aquifers and sodden earth with ease, even while it has creatures engulfed within its body. This functions like the earth glide universal monster rule, except the hyaleth can move through only earth and stone saturated with water. While a hyaleth travels in this manner, creatures it has engulfed that are unable to burrow cannot escape except through magical means.

Engulf (Ex)

A hyaleth can engulf Medium or smaller creatures, but it loses its compression special quality and its racial bonus on Stealth checks when it has a creature engulfed. Engulfed creatures are subject to the hyaleth’s adaptive digestion.

Poison (Ex)

Sting—injury; save Fort DC 21; frequency 1/round for 2 rounds; effect paralysis for 1d3 rounds (the duration of the paralysis is cumulative with each failed save); cure 1 save. The save DC is Constitution-based.

When a creature fails its initial saving throw against the poison delivered by a hyaleth’s sting attack, the hyaleth learns the creature’s Intelligence score.


Environment temperate fresh water or underground
Organization solitary, squad (2–9), or colony (10–200 and 1 hyaleth queen)
Treasure incidental

Hyaleths are translucent, tubular aberrations hailing from deep underground waters. They occasionally travel to the surface, usually during heavy downpours, emerging into lakes, streams, swamps, and sometimes wells. Inquisitive and aggressive, hyaleths come to the surface to explore and to hunt sentient humanoids.

Despite their large size, hyaleth can swim and hide in surprisingly shallow waters, allowing them to remain undetected while approaching their prey. Once it closes in on a target, a hyaleth uses its stinger to deliver a paralyzing neurotoxin before engulfing its victim within its elastic body. Though hyaleths cannot breathe air, they can leave the water and slither along the ground for short periods of time.

An average hyaleth is 16 feet long and weighs about 1,300 pounds.

When not exploring the surface, hyaleths inhabit water-filled caverns and lakes deep underground. It is here that the strange creatures are spawned, hatching from soft-shelled eggs laid by hyaleth queens. In some ways, these caverns are like the hives of social insects, with numerous hyaleths coming and going in a constant stream of activity. Some hyaleths are tasked with caring for the eggs, while others defend the colony or gather food and knowledge for their queen.

Hyaleths share a rudimentary hive mind and prefer to communicate telepathically, although other creatures find their strange and erratic communications difficult to comprehend. Hyaleths aren’t evil, but their little understood motivations and aggressive behavior frequently put them at odds with other races.

Hyaleths eat almost anything they can catch, as their digestive acids can break down nearly any kind of material. Even more than food, hyaleths desire knowledge, which they most often acquire by absorbing the thoughts of creatures they engulf. Hyaleths simply digest any unintelligent or dim-witted creatures they engulf, but they place intelligent creatures into a deep sleep, reading the victim’s thoughts as it falls into slumber. A hyaleth derives great pleasure from drawing out this knowledge, and it subtly changes color while doing so, its transparent body rippling through several hues in delight. When a hyaleth identifies and engulfs a creature with exceptional intelligence, it returns to the deep to deliver the victim to a gigantic hyaleth queen.

Hyaleths over 40 years old gradually lose their flexibility, their translucent bodies becoming cloudy and opaque. Most aging hyaleths return to their colony to be devoured by their queen, but hyaleths prevented from doing so gradually solidify, becoming lifeless lumps of resinous flesh.

Habitat & Society

Hyaleths are social creatures, and few hyaleths enjoy being away from the comfort of a colony for long. Although hyaleth egg tenders and guards are considered valuable to a colony, the colony’s most successful scouts and explorers enjoy the highest status, second only to the queen.

When a thriving hyaleth colony grows beyond a certain size, the colony’s queen lays a special egg that will hatch and grow into another hyaleth queen. A squad of specially appointed hyaleths then takes the egg to a new location many miles away to begin a new colony and serve as the new queen’s guards and scouts.

Hyaleths have a strained relationship with alghollthus. The two races aren’t related, despite their similarities, and hyaleths aren’t as tyrannical or scheming.

Although hyaleths are eager to acquire even a fraction of the immense racial knowledge all alghollthus share, aboleths are too large for hyaleths to consume and too imperious to share knowledge as equals. Alghollthus treat hyaleths with the same disdain as they hold for all other races, subjugating entire hyaleth colonies when it suits their inscrutable purposes.

Hyaleth Queens

Hyaleth queens are larger than normal hyaleths and they have highly superior intellects. They can live for hundreds of years, constantly harvesting vast amounts of information from a continual stream of creatures brought to them by hyaleth scouts. Hyaleth queens are repositories of scattered bits of history and other knowledge surpassing most mortal sages, but given their species’ strange nature and remote habitats, learning the secrets held by a hyaleth queen is extremely difficult.

A hyaleth queen is a Gargantuan hyaleth advanced by adding a +8 racial bonus to all of its mental ability scores, and at least 5 Hit Dice. A hyaleth queen can engulf Large or smaller creatures and can automatically engulf sleeping or helpless creatures expelled by an adjacent hyaleth. A hyaleth queen can selectively apply either option of its adaptive digestion ability to each creature it has engulfed, judging whether each can add to its eclectic store of knowledge or is suitable only as nourishment.

Section 15: Copyright Notice

Pathfinder Adventure Path #130: City in the Lion’s Eye © 2018, Paizo Inc.; Authors: Mikko Kallio, with Eleanor Ferron, Mike Headley, Joe Kondrak, Kalervo Oikarinen, and Liz Smith.

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