Dragon, Sapphire Very Young (CR 18)

Huge Dragon (Earth)
Alignment: Always lawful neutral
Initiative: +4 (Dex); Senses: blindsense 60 ft., darkvision120 ft., low-light vision, and keen senses
Languages: Draconic

AC: 35 (-2 size, +23 natural, +4 Dex), touch 12, flat-footed 31
Hit Dice: 26d12+130 (299 hp); DR: 10/magic
Fort +20, Ref +19, Will +19
Speed: 40 ft., fly 150 ft. (poor), burrow 15 ft., swim 10 ft.
Space: 15 ft./10 ft. (15 ft. with bite)
Base Attack +26; Grapple +43
Attack: 1 Bite +33, 2 claws +28, 2 wings +28, 1 Tail Slap +28 melee; Breath +33 ranged
Damage: 1 bite 2d8+9, 2 claws 2d6+4, 2 wings 1d8+4, 1 tail slap 2d6+13, 1 crush 2d8+13, Breath weapon 16d4 (28)
Special Attacks/Actions: Breath Weapon 16d4 (28); fear (DC 27), SR 25
Abilities: Str 29, Dex 18, Con 21, Int 18, Wis 19, Cha 18
Special Qualities: Electricity immunity, spider climb, sense psychoportation, skate, stone shape, teleport
Feats: #Feats: 9
Skills: Skill points: 110
Advancement: 27-28 HD (Huge)
Climate/Terrain: Inner Planes, underground
Organization: Solitary, pair, or family (1-2 and 2-5 offspring)
Treasure/Possessions: Double Standard

Source: Monster Manual II

Breath Weapon (Su): A sapphire dragon breathes a cone of nearly inaudible sonic energy. In addition to making a Reflex saving throw (DC 15) against sonic damage (4d4), each creature within the cone must succeed at a Will save (same DC) or become panicked for 1d4 rounds. 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.

Dragons ignore the frightful presence of other dragons.

Earth Subtype

This subtype usually is used for elementals and outsiders with a connection to the Elemental Plane of Earth. Earth creatures usually have burrow speeds, and most earth creatures can burrow through solid rock.