rare le gargantuan dragon fire 

Perception +28; darkvision, scent (imprecise) 60 feet, smoke vision

Languages Common, Draconic, Ignan, Terran, Undercommon

Skills Acrobatics +23, Arcana +25, Athletics +32, Crafting +29, Deception +27, Intimidation +29, Nature +24, Stealth +25, Survival +24

Str +8 Dex +3 Con +6 Int +5 Wis +4 Cha +5

Smoke Vision Smoke doesn't impair an underworld dragon's vision; they ignore the concealed condition from smoke.

AC  39; Fort +30, Ref +25, Will +28

HP 295; Immunities fire, paralyzed, sleep

Frightful Presence (aura, emotion, fear, mental) 90 feet, DC 35 (page 305)

Sweltering Heat (arcane, aura, evocation, fire) 10 feet. Each creature that ends its turn in the aura must succeed at a DC 35 Fortitude saving throw or become fatigued while it remains in the aura.

Speed 40 feet, burrow 60 feet, fly 80 feet

Melee [>] jaws +32 (magical, reach 15 feet), Damage 3d10+16 piercing plus 3d6 fire

Melee [>] claw +32 (agile, magical, reach 10 feet), Damage 3d10+16 slashing plus adamantine claws and Grab

Melee [>] tail +32 (magical, reach 25 feet), Damage 3d10+16 bludgeoning plus Grab

Arcane Innate Spells DC 37; 8th continual flame, wall of fire; Cantrips (8th) detect magic

Adamantine Claws The dragon's claws are infused with adamantine. Their claw Strikes ignore half the Hardness of any object hit.

Breath Weapon [>>] (arcane, evocation, fire) The dragon breathes a blast of fire that explodes in a 30-foot burst within 60 feet, dealing 14d6 fire damage (DC 39 basic Reflex save). Creatures that fail the save also take 3d6 persistent fire damage. The dragon can't use Breath Weapon again for 1d4 rounds.

Coiling Frenzy [>>] The dragon makes one claw Strike and one tail Strike in either order, each against the same target. If either Strike hits, the dragon automatically Grabs the target.

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

Greater Constrict [>] 3d10+9 bludgeoning, DC 37 (page 305)

Scorch Earth [>>] (arcane, evocation, fire) The dragon plunges their body into the ground, Burrows up to their Speed, and then scorches the land within a 60-foot emanation. Creatures underground or on the surface in the area take 8d6 fire damage (DC 37 basic Fortitude save), and those who critically fail become enfeebled 1 for 1 minute. Animate dreams (Bestiary 2 18)

Bestiary 3, page 85.