Huge Animal (Aquatic)
Hit Dice: 12d8+74 (128 hp)
Speed: 20ft, Swim 60ft
Armor Class: 18 (-2 size, +2 Dex, +8 natural), touch 10, flat-footed 16
Base Attack/Grapple: +9/+25
Attack: Bite +15 (2d8+12)
Special Attacks: Constrict, Improved Grab
Special Qualities: Blindsight, Keen Scent, Low-light Vision
Saves: Fort +13, Ref +10, Will +9*
Abilities: Str 27, Dex 15, Con 21, Int 1, Wis 12, Cha 6
Skills: Listen +13*, Spot +12*, Swim +16
Feats: Toughness, Improved Natural Attack (Bite), Improved Initiative, Run, Endurance
Challenge Rating: 8
Feared alpha predators, sea serpents are fast, deadly, and can be found anywhere in the sea though they spend most of their time in the deep. It has a serpentine body roughly 50-60ft in length and is up to 2-feet thick, weighing up to 9,000 lbs. It has a spined ridge of fins running down the length of the top of it's body, as well as on either side of it's head like a cobra, and has two sets of longer fins on the underside of it's body that it uses for agile maneuvering, and finally a wide lateral fin at the end of it's tail (similar to a dolphin's) that is it's main source of propulsion. It is covered in armored scales of a deep red color, with black bands like many varieties of viper, while it's underside is a bone white. It's fins are a much paler red, almost orange, and it's spines are also bone white. It's piercing serpentine eyes are yellow. Unlike other serpents, the top of it's head is long and bulging (housing it's echolocation organ).
It can slither around on land like a snake, but prefers not to, as it must hold it's breath out of water. They prefer prey smaller than themselves, but have an unnatural animosity towards vehicles. They can rise up 15ft out of the water (and reach another 10ft beyond that).