Malasynep (CR 7)

Huge Aberration (Aquatic and Cold)
Alignment: Often chaotic evil
Initiative: +2 (Dex); Senses: darkvision 60 ft., heat sense, Listen +15, and Spot +15
Languages: Aquan

AC: 17 (-2 size, +2 Dex, +7 natural), touch 10, flat-footed 15
Hit Dice: 8d8+35 (71 hp)
Fort +6, Ref +6, Will +10
Speed: 10 ft., burrow 40 ft., swim 40 ft.
Space: 15 ft./10 ft.
Base Attack +6; Grapple +21
Attack: Bite +11 melee
Full Attack: Bite +11 melee and slam +6 melee
Damage: Bite 2d6+7, slam 1d6+3
Special Attacks/Actions: Improved grab, psi-like abilities, swallow whole
Abilities: Str 25, Dex 14, Con 19, Int 17, Wis 18, Cha 18
Special Qualities: Amphibious, immunity to cold, vulnerability to fire
Feats: Combat Casting; Lightning Reflexes; Toughness
Skills: Concentration +1S, Intimidate +15, Knowledge (any one) +14, Listen +15, Spot +15, and Swim +15
Advancement: 9-18 HD (Huge); 19-24 HD (Gargantuan)
Climate/Terrain: Cold aquatic
Organization: Solitary or brood (3-4)
Treasure/Possessions: Double standard

Source: Frostburn

Improved Grab (Ex): To use this ability, a malasynep must hit a Large or smaller foe with its bite attack. It can then attempt to start a grapple as a free action without provoking attacks of opportunity. If it wins the grapple check, it establishes a hold and can attempt to swallow the foe the following round.

Psi-Like Abilities: At will - energy emanation (cold only, 3d6+3, DC 18); 1/day - energy flash (cold only, 9d6+9; DC 19). Manifester level 9th. The save DCs are Charisma-based.

Swallow Whole (Ex): A malasynep can try to swallow a grabbed opponent of Large or smaller size by making a successful grapple check. Once inside, the opponent takes 2d6+7 points of crushing damage plus 1d6 points of cold damage and 1d6 points of acid damage per round from the malasynep's gizzard. A swallowed creature can cut its way our by using a light slashing or piercing weapon to deal 20 points of damage to the gizzard (AC 13). Once the creature exits, muscular action closes the hole; other swallowed opponents must cut their own way our. A Huge malasynep's interior can hold 1 Large, 4 Medium, 16 Small, 64 Tiny, or 256 Diminutive or smaller opponents.

Amphibious (Ex): Although a malasynep breathes with gills, it can survive indefinitely out of the water.

Heat Sense (Su): A malasynep can automatically sense heat sources within 60 feet, as the spell detect fire. It senses only the presence or absence of heat, but if it chooses to use a standard action to concentrate on this ability, it can establish the number and location of heat auras and the strength of each in the second and third rounds of concentration.

Invisible creatures whose location is pinpointed by heat sense still have total concealment from the malasynep.

Skills: A malasynep has a +8 racial bonus on any Swim check to perform some special action or avoid a hazard. It can always choose to take 10 on a Swim check, even if distracted or endangered. It can use the run action while swimming, provided it swims in a straight line.

A malasynep attacks by slamming its enormous body into its opponents or by biting foes with its triple rows of razor-sharp teeth, although it first tries to weaken enemies with its psionic powers.

Aquatic Subtype

Creatures with the aquatic subtype always have swim speeds and thus can move in water without making Swim checks. An aquatic creature can breathe underwater. It cannot also breathe air unless it has the amphibious special quality.

Cold Subtype

A creature with the cold subtype has immunity to cold. It has vulnerability to fire, which means it takes half again as much (+50%) damage as normal from fire, regardless of whether a saving throw is allowed, or if the save is a success or failure.