rare ln gargantuan amphibious dragon elemental water 

Perception +32; darkvision, scent (imprecise) 60 feet

Languages Aquan, Common, Draconic, Sylvan, Utopian

Skills Acrobatics +28, Athletics +32, Deception +32, Intimidation +34, Nature +30, Society +30, Survival +29

Str +9 Dex +5 Con +6 Int +5 Wis +5 Cha +6

AC  40; Fort +31, Ref +30, Will +30

HP 330; Immunities acid, paralyzed, sleep

Frightful Presence (aura, emotion, fear, mental) 90 feet, DC 36

Brine Spit [R] Trigger A creature the brine dragon observes within 30 feet uses a concentrate action; Effect The dragon spits a glob of caustic salt water at the creature. The creature takes 7d6 acid damage (DC 36 basic Reflex save). On a failure, the concentrate action is disrupted.

Speed 50 feet, fly 140 feet, swim 70 feet

Melee [>] jaws +34 (acid, magical, reach 20 feet), Damage 3d10+17 piercing plus 5d4 acid

Melee [>] claw +34 (agile, magical, reach 15 feet), Damage 3d10+17 slashing

Melee [>] tail +32 (magical, reach 25 feet), Damage 3d12+17 bludgeoning

Melee [>] wing +32 (magical, reach 20 feet), Damage 2d12+17 piercing

Primal Innate Spells DC 38, attack +30; 6th hydraulic torrent; 5th control water (×3), traefibroum's curse; 4th hydraulic push (at will), obscuring mist (at will)

Breath Weapon [>>] (acid, evocation, primal) The dragon breathes a spray of acidic salt water that deals 18d6 acid damage in a 120-foot line (DC 38 basic Reflex save). They can't use Breath Weapon again for 1d4 rounds.

Capsize [>] (attack) The dragon tries to capsize an adjacent aquatic vessel of their size or smaller. They must succeed at an Athletics check with a DC of 35 (reduced by 5 for each size smaller the vessel is than the dragon) or the pilot's Sailing Lore DC, whichever is higher.

Desiccating Bite [>>] The dragon makes a jaws Strike. On a hit, the target takes 6d6 persistent acid damage, and is sickened 3 from the pain of salt and brine in its wounds.

Draconic Frenzy [>>] The dragon makes two claw Strikes and one wing Strike in any order.

Draconic Momentum The dragon recharges their Breath Weapon whenever they score a critical hit with a Strike.

Painful Strikes (acid) The brine dragon's body is encrusted with salty, acidic crystals. When a target takes damage from one of the dragon's melee Strikes, it must succeed at a DC 38 Fortitude Save or be stunned 1 (stunned 3 on a critical failure). The target then becomes temporarily immune for 1 minute.

Bestiary 2, page 88.