Dragon, White Ancient (CR 17)

Huge Dragon (Cold)
Alignment: Always Chaotic Evil
Initiative: +0; Senses: blindsense 60 ft., darkvision120 ft., low-light vision, and keen senses
Languages: Draconic

AC: 37 (-2 size, +29 natural), touch 8, flat-footed 37
Hit Dice: 30d12+80 (375 hp); DR: 15/magic
Fort +23, Ref +17, Will +19
Speed: 60 ft., fly 200 ft. (poor), swim 60 ft., burrow 30 ft.
Space: 15 ft./10 ft. (15 ft. with bite)
Base Attack +27; Grapple +45
Attack: 1 Bite +39, 2 claws +34, 2 wings +34, 1 Tail Slap +34, 1 crush +34 melee; Breath +39 ranged
Damage: 1 bite 2d8+11, 2 claws 2d6+5, 2 wings 1d8+5, 1 tail slap 2d6+16, 1 crush 2d8+16, Breath weapon 20d6 (31)
Special Attacks/Actions: Breath weapon, fear (DC 27), SR 24
Abilities: Str 33, Dex 10, Con 23, Int 14, Wis 15, Cha 14
Special Qualities: Cold subtype, icewalking, Fog cloud, Gust of wind, Freezing fog, Wall of ice, CL 9
Feats: #Feats: 11
Skills: Skill points: 66
Advancement: 31-32 HD (Huge)
Climate/Terrain: Any cold land and underground
Organization: Solitary, pair, or family (1-2 and 2-5 offspring)
Treasure/Possessions: Double Standard

Source: Monster Manual

Breath Weapon (Su): A white dragon has one type of breath weapon, a cone of cold (10d6 cold damage, Reflex save for half damage DC 31). Using a breath weapon is a standard action. Once a dragon breathes, it can't breathe again until 1d4 rounds later. A blast from a breath weapon always starts at the dragon's mouth and extends in a direction of the dragon's choice.

Frightful Presence (Ex): A young adult or older dragon can unsettle foes with its mere presence. The ability takes effect automatically whenever the dragon attacks, charges, or flies overhead. Creatures within a radius of 300 feet are subject to the effect if they have fewer HD than the dragon (30).

A potentially affected creature that succeeds at a Will save (DC 27) remains immune to that dragon's frightful presence for one day. On a failure, creatures with 4 or fewer HD become panicked for 4d6 rounds and those with 5 or more HD become shaken for 4d6 rounds.

Dragons ignore the frightful presence of other dragons.

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.