Dragon, Shadow Great Wyrm (CR 24)

Gargantuan Dragon
Alignment: Always chaotic evil
Initiative: +0; Senses: blindsense 60 ft., darkvision120 ft., low-light vision, and keen senses
Languages: Draconic

AC: 46 (-4 size, +40 natural), touch 6, flat-footed 46
Hit Dice: 37d12+296 (536 hp); DR: 20/magic
Fort +29, Ref +21, Will +32
Speed: 80 ft., fly 150 ft. (clumsy)
Space: 40 ft./15 ft.
Base Attack +37; Grapple +61
Attack: 1 bite +45, 2 claws +40, 2 wings +40, 1 tail slap +40, 1 crush +40, 1 tail sweep +40
Damage: 1 bite 4d6+12, 2 claws 2d8+6, 2 wings 2d6, 1 tail slap 2d8, 1 crush 4d6, 1 tail sweep 2d6
Special Attacks/Actions: Breath weapon 8(DC 39)
Abilities: Str 35, Dex 10, Con 27, Int 32, Wis 32, Cha 33
Special Qualities: Energy drain immunity, Shadow blend, Mirror Image, Dimension door, Nondetection, Shadow walk, Create shadows, Frightful Presence DC39, SR 33
Feats: #Feats: 13
Skills: Skill points: 413
Advancement: 38+ HD (Colossal)
Climate/Terrain: 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: Triple Standard

Source: Draconomicon

Breath Weapon (Su): A shadow dragons breath weapon is a cone of billowing, smoky shadows with an energy drain effect. Creatures within the cone gain 8 negative levels: the saving throw to remove the negative level is 39. A successful Reflex save (DC 39) reduces the number of negative levels by half (round down).

Shadow Blend (Su): During any conditions other than full daylight, a shadow dragon can disappear into the shadows, giving it nine-tenths concealment. Artificial illumination, even a light or continual flame spell, does not negate this ability. A daylight spell, however, will.

Create Shadows (Su): Three times per day, a great wyrm shadow dragon can conjure a mass of leaping shadows with a radius of 100 yards and a duration of 1 hour (this is a creation effect). All normal and magical light sources are negated within this radius. All characters and creatures gain a +4 bonus on their Hide checks within the shadows, and can hide even if directly observed. Shadow dragons and other creatures with ties to the Plane of Shadow gain total concealment within the shadows (50% miss chance), though they can move and attack normally. Their attacks gain a +2 bonus and deny their opponents any Dexterity bonus to AC, because they are considered invisible.