Sea Serpent, Lantern, Great Wyrm (CR 25)
Colossal Dragon (Water)
Alignment: Always lawful evil
Initiative: +0
AC: 41 (-8 size, +39 natural), touch 2, flat-footed 41
Hit Dice: 39d12+390 (643 hp); DR: 5/magic
Fort +31, Ref +21, Will +27
Speed: 40 ft., swim 120 ft.
Space: 80 ft./15 ft.
Base Attack +39; Grapple +71
Attack: 1 bite +47, 2 claws +42 + 1 tail slap +42
Damage: 1 bite 4d8+16, 2 claws 4d6+8, 1 tail slap 4d6
Special Attacks/Actions: Breath weapon 23d6 (39), Constrict
Abilities: Str 43, Dex 10, Con 31, Int 22, Wis 23, Cha 22
Special Qualities: Amphibious, color spray, Dispel Magic, Hypnotic Pattern, DR 10/magic, Prismatic Spray, DR 15/magic, DR 20/magic, Hold Monster, SR 31, Fear aura (DC 35)
Feats: #Feats: 14
Skills:
Class Skills: Hide, Intimidate, Move Silently, and Skill points: 240
Advancement: 40+ HD
Climate/Terrain: Temperate Aquatic
Organization: Solitary (1 dragon, any age), clutch (1d4+1 wyrmlings, very young, young, juvenile, or young adults), family (pair of mature adults and 1d4+1 offspring)
Treasure/Possessions: Double Standard
Source:
Dragon #345
Amphibious (Ex): Sea serpents can breathe air as easily as they breathe water.
Constrict (Ex): A sea serpent of Medium size or larger deals damage with a successful grapple check. The amount of damage dealt depends upon the creature's size, as indicated on the following chart. The sea serpent adds 1-1/2 times its Strength bonus on damage rolls made to constrict.
| Size | Constrict Damage |
| Medium | 1d8 |
| Large | 2d8 |
| Gargantuan | 4d8 |
| Colossal | 6d8 |
Lantern sea serpents carefully plan before an attack. Using their spell-like abilities, lantern serpents soften up their prey, weakening their victims before they strike. Then they attack physically, destroying whatever is left of their prey.
Improved Grab (Ex): To use this ability, the sea serpent must hit with its bite or tail slap attacks. It can then attempt to start a grapple as a free action without provoking an attack of opportunity. If it wins a grapple check, it establishes a hold. If it gets a hold with its bite it can attempt to swallow the foe the following round. If it gets a hold with its tail slap it can constrict.
Swallow Whole (Ex): A sea serpent can attempt to swallow an opponent at least two size categories smaller than itself by making a successful grapple check. Once inside, the opponent takes bite damage plus 1d8 points of acid damage every round from the serpent's digestive tract. A swallowed creature can attempt to cut its way out by using a light slashing or piercing weapon to deal 3 points of damage per age category of the sea serpent to its digestive tract (AC 15). Once the creature exits, muscular action closes the hole; other swallowed opponents must cut their own ways out.
A sea serpent's digestive tract can hold up to one opponent of two size categories smaller than itself and four times as many of each size category below that. For example, a Huge sea serpent's digestive tract can hold 1 Medium, 4 Small, 16 Tiny, or 64 Diminutive or smaller opponents.
Breath Weapon (Su): A lantern sea serpent has one kind of breath weapon, a line of crackling red lightning. Creatures caught in the line of electricity receive a Reflex save for half damage.
Spell-Like Abilities: At will - color spray, hold monster, hypnotic pattern; 3/day-dispel magic, prismatic spray.
Skills: Hide, Intimidate, and Move Silently are considered class skills for lantern sea serpents.
Water Subtype
This subtype usually is used for elementals and outsiders with a connection to the Elemental Plane of Water. Creatures with the water subtype always have swim speeds and can move in water without making Swim checks. A water creature can breathe underwater and usually can breathe air as well.