Seetangeist

A mound of rotting kelp and drowned carrion given malign half-life, the seetangeist drifts through the deep as a slick of foul water that poisons everything it touches.

Level 12

Perception +19 · Senses darkvision, wavesense (imprecise) 100 feet · Skills Athletics +22

HP 160 · Immunities death effects, disease, mental, paralyzed, poison, precision, prone, unconscious · Resistances bludgeoning 5, cold 10, fire 10, slashing 10, piercing 10 · Weaknesses area 10, splash damage 10

Speed swim 40 feet

• Necrotic Runoff (aura, poison) 60 feet. A seetangeist secretes foul fluids into the surrounding water, poisoning it. A creature that enters or starts its turn in the aura must succeed at a DC 29 Fortitude save or become sickened 2 (sickened 3 on a critical failure). Creatures that breathe water take a –2 circumstance penalty to this saving throw. As long as a creature remains in the aura, it can't reduce its sickened condition below 1.