uncommon ne huge aquatic mindless swarm undead 

Perception +19; darkvision, wavesense (precise) [object Object] feet

Skills Athletics +22

Str +4 Dex +4 Con +7 Int -5 Wis +3 Cha +2

AC  32; Fort +25, Ref +22, Will +19

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

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. A creature that succeeds at its save is temporarily immune for 1 minute.

Speed swim 40 feet

Putrid Assault [>] Each enemy in the seetangeist's space takes 3d6 slashing and 3d6 poison damage (DC 32 basic Reflex save). A creature that fails this save also takes 1d12 persistent poison damage.

Book of the Dead, page 165.