uncommon ce gargantuan amphibious dragon 

Perception +28; darkvision, scent (imprecise) 60 feet, true seeing

Languages Aklo, Draconic, Sylvan

Skills Acrobatics +27, Athletics +33, Stealth +29

Str +9 Dex +5 Con +8 Int -3 Wis +6 Cha +7

AC  40; Fort +30, Ref +28, Will +24

HP 315, regeneration 10 (deactivated; Immunities cold, curse, paralyzed, sleep; Weaknesses cold

Curse of Stolen Breath (curse, primal, water) When a creature slays a fjord linnorm, it must succeed at a DC 41 Will save or become unable to ever breathe underwater (either via a natural ability or a spell such as water breathing). In addition, the victim can hold its breath only half as long as normal, and whenever it holds its breath it becomes sickened 2.

Attack of Opportunity [R] Tail only.

Speed 35 feet, fly 75 feet, swim 50 feet; freedom of movement

Melee [>] jaws +33 (magical, reach 20 feet), Damage 3d12+17 piercing plus fjord linnorm venom

Melee [>] claw +33 (agile, magical, reach 20 feet), Damage 3d10+17 slashing

Melee [>] tail +33 (agile, magical, reach 25 feet), Damage 3d6+15 bludgeoning plus Improved Grab

Primal Innate Spells DC 37; Constant 

Breath Weapon [>>] (cold, evocation, primal) The fjord linnorm expels a 120-foot line of icy bile, dealing 17d6 cold damage to creatures within the area (DC 37 basic Reflex save) Any creature that fails its save is covered by the ice, which freezes and fuses with the creature's skin, giving it a –10-foot penalty to Speed. A creature can Escape or Force Open the ice (DC 34) to free itself; otherwise, the ice remains for 1 minute. The fjord linnorm can't use Breath Weapon again for 1d4 rounds.

Fjord Linnorm Venom (cold, poison) Saving Throw DC 37 Fortitude; Maximum Duration 10 rounds; Stage 1 4d6 cold damage and clumsy 1 (1 round); Stage 2 6d6 cold damage and clumsy 2 (1 round)

Bestiary 2, page 165.