Stygian Serpent
CREATURE 12Variant sea serpent
These fabled beasts resemble massive snakes with long rows of finned spines down their back. Temperamental and territorial, sea serpents can capsize a boat with ease, and most won't hesitate to do so when hungry or threatened. Stories abound of aggrieved captains who spend their entire lives hunting down the elusive monster that sunk their ships and took their livelihoods. These hunts rely on rumors and glimpses of the beasts, as few survive the catastrophes wrought by sea serpents.
While many fishermen's tales paint sea serpents as divinely appointed guardians of the ocean or as evil and demonic agents, the truth is that most sea serpents are simply very large beasts with a knack for avoiding magical detection.
A sea serpent automatically tries to counteract any detection, revelation, or scrying divination attempted against it, using its Stealth modifier for its counteract modifier.
The serpent is immune to effects of the River Styx.
The sea serpent attempts to capsize an aquatic vessel of its size or smaller that it's adjacent to. It must succeed at an DC 35 Athletics check with a DC of 35 (reduced by 5 for each size smaller than the sea serpent) or the pilot's Sailing Lore DC, whichever is higher.
1d10+14 bludgeoning, DC 32 basic Fortitude
The monster deals the listed amount of damage to any number of creatures Grabbed or Restrained by it. Each of those creatures can attempt a basic Fortitude save with the listed DC.
Huge, 2d10+6 bludgeoning, Rupture 20
The monster attempts to swallow a creature of the listed size or smaller that it has grabbed or restrained in its jaws or mouth. If a swallowed creature is of the maximum size listed, the monster can't use Swallow Whole again. If the creature is smaller than the maximum, the monster can usually swallow more creatures; the GM determines the maximum. The monster attempts an Athletics check opposed by the grabbed creature's Reflex DC. If it succeeds, it swallows the creature. The monster's mouth or jaws no longer grab a creature it has swallowed, so the monster is free to use them to Strike or Grab once again. The monster can't attack creatures it has swallowed.
A swallowed creature is Grabbed, is Slowed 1, and has to hold its breath or start suffocating. The swallowed creature takes the listed amount of damage when first swallowed and at the end of each of its turns while it's swallowed. If the victim Escapes this ability's grabbed condition, it exits through the monster's mouth. This frees any other creature grabbed in the monster's mouth or jaws. A swallowed creature can attack the monster that has swallowed it, but only with unarmed attacks or with weapons of light Bulk or less. The swallowing creature is Off-Guard against the attack. If the monster takes piercing or slashing damage equaling or exceeding the listed Rupture value from a single attack or spell, the swallowed creature cuts itself free. A creature that gets free by either Escaping or cutting itself free can immediately breathe and exits the swallowing monster's space.
Effect: Engulf and Swallow Whole
If the monster dies, a swallowed creature can be freed by creatures adjacent to the corpse if they spend a combined total of 3 actions cutting the monster open with a weapon or unarmed attack that deals piercing or slashing damage.
The monster can instead use Grab and choose one creature it's grabbing or restraining with an appendage that has Grab to automatically extend that condition to the end of the monster's next turn.