Spine-frilled neck arching up from the water like a snake ready to strike, this ship-sized serpent hisses a challenge.
Sea Serpent CR 12
N Gargantuan magical beast (aquatic)
Init +6; Senses darkvision 120 ft., low-light vision; Perception +8
AC 25, touch 8, flat-footed 23 (+2 Dex, +17 natural, –4 size)
hp 187 (15d10+105)
Fort +16, Ref +13, Will +7
Defensive Abilities elusive; Immune cold; Resist fire 30
Speed 20 ft., swim 60 ft.
Melee bite +23 (4d8+22/19–20 plus grab), tail slap +18 (3d6+6 plus grab)
Space 20 ft.; Reach 20 ft.
Special Attacks capsize, constrict (3d6+18), swallow whole (4d8+18 bludgeoning damage, AC 18, hp 18)
Str 34, Dex 14, Con 25, Int 2, Wis 11, Cha 11
Base Atk +15; CMB +31 (+35 grapple); CMD 43 (can't be tripped)
Feats Improved Bull Rush, Improved Critical (bite), Improved Initiative, Iron Will, Lightning Reflexes, Power Attack, Skill Focus (Stealth), Stealthy
Skills Perception +8, Stealth +13, Swim +20
Environment any ocean
Capsize (Ex) A sea serpent can attempt to capsize a boat or ship of its size or smaller by ramming it as a charge attack and making a combat maneuver check. The DC of this check is 25 or the result of the boat captain's Profession (sailor) check, whichever is higher.
Elusive (Su) Sea serpents have long been the stuff of maritime legends, but despite countless attempts to hunt them, they are rarely encountered unless they wish it. As a full-round action while in water, a sea serpent can move up to its run speed (300 ft.) without leaving any trace of its passing (identical in effect to a pass without trace). An elusive sea serpent gains a +40 circumstance bonus to its Stealth check. In addition, except when in combat, a sea serpent is considered to be under the effects of a nondetection spell. Both of these spell effects are at caster level 20th and cannot be dispelled.
Tales of immense sea serpents have colored the accounts of seagoing folk since the first ship sailed beyond sight of land. Yet proof of these immense and elusive creatures is remarkably difficult to come by, for not only is the ocean vast and the true sea serpent rare, but these creatures are quite adept at both avoiding capture and destroying ships bent on such a daunting task. Due to the sea serpent's hermitic nature, many sailors take to ascribing the sighting of such a beast to an omen, although whether the sighting portends peril or providence depends as much upon the ship's morale as it does anything else—the sea serpent itself has little interest in prophecy, and only its hunger determines how dangerous its proximity to a curious ship can be.
Although sea serpents are little more than animals, they possess about them an air of mysticism that even old salts and cynics are forced to admit quickens the heart and buoys (or sinks) the spirit. Reports of sea serpent sightings are just as likely to encourage travel as they are to cause panic among seafarers, as explorers and adventurers flock to the site in hopes of sighting such a legendary creature.
Typical sea serpents are 60 feet in length and weigh 4,500 pounds, but their upward size limit is unknown. Certainly, the sea is a vast and mysterious place more than capable of supporting whales and other such leviathans, and tales of sea serpents that exceed lengths of 300 feet or more are not unheard of. You can generate statistics for a sea serpent of such tremendous size by applying the advanced simple template or the giant simple template to the statistics presented here. Alternatively, you can advance this sea serpent to Colossal size, increasing its Hit Dice to 25 and its CR to 18.