Sailor’s Bane
From beneath the waters bursts an inky tendril of ooze that begins to tear the ship apart…

Sailor’s Bane (CR 9; XP 6,400)
N Huge ooze
Init -1; Senses blindsight 120 ft.; Perception -5
Defense
AC 7, touch 7, flat-footed 7
(-1 Dex, -2 size)
hp 119 (14d8+56)
Fort +7, Ref +2, Will -2
Defensive Abilities ooze traits; Immune fire
Vulnerable cold
Offense
Speed 10 ft., swim 40 ft.
Melee slam +17 (2d6+13 plus 2d6 acid plus grab)
Space 15 ft.; Reach 15 ft.
Special Attacks constrict (2d6+9 plus 2d6 acid), devour hull, engulf (R-DC 26, 2d6+13 plus 2d6 acid), implant
Statistics
Str 28, Dex 9, Con 18, Int —, Wis 1, Cha 1
Base Atk +10; CMB +21; CMB 30 (can’t be tripped)
SQ swimming hazard
Ecology
Environment aquatic
Organization solitary
Treasure none
Special Abilities
Devour Hull (Ex) The enzymatic acids produced by the sailor’s bane deals 10d6 points of acid damage to wooden objects per round of contact.
Implant (Ex) The sailor’s bane may choose to not deal engulf damage to a creature, instead implanting them with an embryonic form of sailor’s bane ooze. The victim must make a Fortitude save (DC 21) or become infected. The embryonic ooze deals 1 point of Constitution drain each day until the victim is reduced to 0 Constitution, at which point the ooze consumes the rest of its host’s body and emerges fully formed. It then migrates to an ocean or lake to continue its life cycle. A heal spell can kill the embryonic ooze, but no other forms of medical or magic treatment can save the victim. The save DC is Constitution-based.
Swimming Hazard (Ex) Any creature swimming within 100 ft. of the sailor’s bane must make a Swim check (DC 26) each round or be pulled 20 ft. closer to the ooze until they are eventually engulfed. The save DC is Strength-based.

The habits of this water-borne terror are specific enough that most scholars assume it is an engineered creature designed to attack and sink water-borne craft, or perhaps a black pudding evolved into a semi-aquatic form. Appearing as a night-black blob or slick of dense protoplasm, sailor’s bane, as these oozes are known, are unable to descend into deep, cold water, and, indeed, cannot breathe water, staying at the surface of the body of water they inhabit or just below it. They are not particular as to whether their homes are fresh or salt water, though they are most often found in the ocean, hunting the sailing vessels of humanoids. All sailors have a deep fear of being implanted, and crews are under strict orders to kill those that have been.

On Porphyra
A variety of black pudding modified in desperation by Najimite cultists during the NewGods War, sailor’s bane were too few in number to turn the tide of maritime war. The few that saw action were used by ice giants, who could repel and manipulate them with their powers of cold. Many ships that ply the waters around whatever location the Haunted Seas occupies keep many vials of liquid ice on hand to speed the removal of sailor’s bane from their ships, though they are still greatly feared.