Dragon, Ectoplasmic Great Wyrm (CR 27)

Colossal Dragon (Fire)
Alignment: Always chaotic neutral
Initiative: +2 (Dex); Senses: blindsense 60 ft., darkvision120 ft., low-light vision, and keen senses
Languages: Draconic

AC: 44 (-8 size, +2 Dex, +40 natural), touch 4, flat-footed 42
Hit Dice: 41d12+410 (676 hp); DR: 20/magic
Fort +32, Ref +24, Will +30
Speed: 40 ft., fly 250 ft. (clumsy), swim 80 ft.
Space: 80 ft./15 ft.
Base Attack +41; Grapple +75
Attack: 1 bite +51, 2 claws +46, 2 wings +46, 1 tail slap +46, 1 crush +46, 1 tail sweep +46
Damage: 1 bite 4d8+18, 2 claws 4d6+9, 2 wings 2d8, 1 tail slap 4d6, 1 crush 4d8, 1 tail sweep 2d8
Special Attacks/Actions: Breath weapon 24d8 (40)
Abilities: Str 47, Dex 14, Con 31, Int 32, Wis 27, Cha 25
Special Qualities: Planar travel, ectoplasm immunity, Ectoplasmic cocoon, Chameleon, Negate psionics, Dismiss ectoplasm, Energy barrier, Catapsi, whitefire aura 20d4, Mass cocoon, Manifester Lvl 19th, PR 31, SR 31, Fear aura (DC 37)
Feats: #Feats: 14
Skills: Skill points: 457
Advancement: 42+ HD.
Climate/Terrain: Demiplane of Ectoplasm, Astral Plane, underground
Organization: Solitary (1 dragon, any age), clutch (1d4+1 wyrmlings, very young, young, juvenile, or young adults), family (pair of mature adults and 1d4+1 offspring)
Treasure/Possessions: Double standard

Source: Web

Breath Weapon (Su): An ectoplasmic dragon has one breath weapon: a burst of whitefire. The radius and range of the breath weapon are listed in the chart. They spit out a glob of raw ectoplasm that explodes upon reaching the desired range.

Dragon Size*Maximum RangeRadius
Tiny*30 feet5 feet
Small*40 feet10 feet
Medium60 feet15 feet
Large80 feet20 feet
Huge100 feet25 feet
Gargantuan120 feet30 feet
Colossal140 feet35 feet

* Though ectoplasmic dragons cannot be smaller than Medium, these sizes were included for completeness.

Planar Travel (Su): Ectoplasmic dragons have the innate ability to pass instantly between the Material Plane and the Astral Plane as a standard action.

Psionics (Sp): 3/day -- chameleon, dismiss ectoplasm, ectoplasmic cocoon, negate psionics; 2/day -- energy barrier; 1/day -- catapsi, mass cocoon. Manifester level varies by age; save DC 10 + dragon's Intelligence modifier + power level. An ectoplasmic dragon manifests powers and gains additional attack and defense modes as if it were a psion with Metacreativity as its primary discipline.

Attack/Defense Modes: Id insinuation/mental barrier.

Whitefire Aura (Su): The ectoplasmic dragon can initiate its whitefire aura once per day as a standard action. It lasts 1 round per age category of the dragon. While the aura lasts, any creature striking the dragon with a natural or a handheld weapon deals normal damage, but at the same time the attacker takes the whitefire damage listed. If the attacker makes a successful Reflex save (DC same as frightful presence), it reduces damage by half.

Ectoplasm Immunity (Ex): An ectoplasmic dragon is not effected by the dismiss ectoplasm power.

Fire Subtype

A creature with the fire subtype has immunity to fire. It has vulnerability to cold, which means it takes half again as much (+50%) damage as normal from cold, regardless of whether a saving throw is allowed, or if the save is a success or failure.