All | Unique
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z
Families | Templates | Types | Subtypes | Universal Monster Rules

Estuarine Worm, Estuarine Worm (Ahket Form)

As thick and tall as a towering palm tree, this mud-colored worm hisses through a fanged mouth. Atop its head, a small protuberance shines like a star.

Estuarine Worm (Ahket Form) CR 10

Source Pathfinder #82: Secrets of the Sphinx pg. 86
XP 9,600
N Huge magical beast (aquatic)
Init +7; Senses darkvision 60 ft., low-light vision, tremorsense 30 ft.; Perception +11


AC 22, touch 11, flat-footed 19 (+3 Dex, +11 natural, –2 size)
hp 126 (11d10+66)
Fort +13, Ref +10, Will +6; +4 vs. enchantment
Defensive Abilities willful; DR 5/piercing or slashing; Resist acid 10, fire 10


Speed 30 ft., burrow 20 ft., swim 20 ft.
Melee bite +20 (2d8+11/19–20 plus grab), tail slap +15 (2d8+5)
Space 15 ft., Reach 10 ft.
Special Attacks constrict (2d8+11), guiding star (DC 14)


Str 32, Dex 16, Con 23, Int 1, Wis 13, Cha 8
Base Atk +11; CMB +24; CMD 37 (can’t be tripped)
Feats Improved Critical (bite), Improved Initiative, Iron Will, Power Attack, Skill Focus (Perception), Skill Focus (Stealth)
Skills Perception +11, Stealth +8 (+16 in water), Swim +19; Racial Modifiers +8 Stealth in water
SQ amphibious, seasonal transformation


Environment warm marshes and rivers
Organization solitary, pair, or nest (3–6)
Treasure incidental

Special Abilities

Guiding Star (Su) When the estuarine worm is in ahket form, its bioluminescence attracts weak-minded creatures. Any creature within 120 feet that attempts to move during its turn must succeed at a DC 14 Will save or be forced to move toward the estuarine worm instead of in its intended direction. This ability is otherwise treated a gaze attack. This ability is a mind-affecting illusion (pattern) effect, though vermin are not immune to this effect. The estuarine worm can activate and deactivate this ability as a free action. The save DC is Charisma-based.

Seasonal Transformation (Ex) An estuarine worm has two forms: ahket (wet season) and shemu (dry season). In its shemu form, the estuarine worm is one size category smaller than when it’s in its ahket form. Further, its Strength and Dexterity decrease by 8 and it loses its damage reduction. It also loses its guiding star ability and its willful special quality. Its natural armor bonus increases by 8 and it gains DR 15/bludgeoning. In addition, all of the creature’s movement speeds are decreased by 10 feet.

An estuarine worm assumes its shemu form if it goes 24 hours without exposure to water. An estuarine worm that is targeted by a control water (lower water), greater polymorph, flesh to stone, or transmute mud to rock spell immediately shifts to its shemu form (instead of experiencing the spell’s normal effect).

An estuarine worm takes on ahket form if it is submerged in water for 24 hours. An estuarine worm that is targeted by a control water (raise water), greater polymorph, stone to flesh, or transmute rock to mud spell immediately shifts to its ahket form (instead of experiencing the spell’s normal effect).

Willful (Ex) In ahket form, an estuarine worm gains a +4 competence bonus to Will saves against enchantment spells and effects.


When Alboras, one of the brightest navigable stars, returns to the night sky, it is a sure sign the River Sphinx will soon flood its banks and replenish the land after the harvest. The inundation also revives the rare but deadly estuarine worms. During the wet season, which is called akhet in Osiriani, the giant worms hunt the flooded plains. When the waters recede and Alboras disappears below the horizon again, the estuarine worms retreat as well. During shemu, the dry season, they enter a semi-torpid state and lie buried beneath the dry soil for protection.

A typical estuarine worm measures 25 feet long and 3 feet wide during the wet season. The worms have a bioluminescent organ atop their heads. At night, the tiny, flickering light might be mistaken for a star low on the horizon. When the dry season comes, the estuarine worm contracts to become half as long and half as wide. Its skin, once soft and spongy like wet mud, becomes as hard as stone.


Estuarine worms are most active when the River Sphinx is at its highest levels and crests its banks. Though the farmers leave when their lands flood, those who live on the edges of the flood plain, as well as those who sail the river, are still at risk of attack by these predators. Estuarine worms bury themselves in the mud during the day and emerge to hunt at night when it is cooler. The carnivorous worms eat whatever they can find, from fish and frogs, to livestock and people. They have even been known to gorge on crocodiles and hippopotamuses, after which they bury themselves for a time in order to digest their hefty meals. The lights on their heads attract small animals above and below the water, which in turn can attract larger prey. Stories are told of travelers who mistake the light for Alboras and navigate their small riverboats right into the maw of a worm.

As the floods recede, the estuarine worms become less active. When the land above them is no longer underwater, the worms remain buried in the moist soil. For the rest of the year, they live off fat and water stored during the wet season. The worms’ flesh contracts, becoming denser in the process. It is commonly believed that the worms, like the soil, harden from dehydration, but it is, in fact, a natural defense mechanism. Though they might seem to be asleep, estuarine worms remain a danger in the dry season. When the worm’s resting spot is too shallow or a plow digs too deep, farmers risk disturbing a worm in its hibernation. Though the worms may not be as agile or as hungry during this time, they are still dangerous predators.

Habitat & Society

Estuarine worms are typically solitary hunters. They reproduce parthenogenetically, and thus have little need for contact with others of their kind. Estuarine worms reproduce rarely, but birth large numbers of offspring when they do. Most of the spawn, however, are eaten by other predators long before they reach full size. When multiple worms are found together (usually because of lower-than-normal floodwater), only the alpha worm uses its bioluminescence. This sign of dominance also keeps potential prey from being drawn to multiple light sources.

Several cults in Osirion keep estuarine worms as sacred beasts in their secret temples. Worshipers of both Lamashtu and Rovagug believe it was their respective god who birthed these worms. Members of the Old Cults revere estuarine worms for their connection to the star Alboras and the Great Old One who supposedly dwells there. The cultists seek out the worms during the season of shemu, when the worms are less violent and more tractable. A combination of brute force and magic are necessary to find, exhume, and contain these elusive creatures. In captivity, estuarine worms can be made to change form regardless of the season through the application or exclusion of water. The high priests of these cults also know certain spells that can trigger an immediate change. The cultists connect to their god through the worms, offering sacrifices to them and reading omens in their violent squirming. The worms serve as guards against intruders, and can also be used as weapons against the cult’s enemies.

Creatures in "Estuarine Worm" Category

Estuarine Worm (Ahket Form)10
Estuarine Worm (Shemu Form)10

Estuarine Worm

As thick and tall as a towering palm tree, this mud-colored worm hisses through a fanged mouth. Atop its head, a small protuberance shines like a star.