Dragon, Black Adult (CR 10)

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


AC: 27 (-1 size, +18 natural), touch 9, flat-footed 27
Hit Dice: 19d12+76 (199 hp); DR: 5/magic
Fort +15, Ref +11, Will +12
Speed: 60 ft., fly 150 ft., (poor), swim 60 ft.
Space: 15 ft./10 ft. (15 ft. with bite)
Base Attack +19; Grapple +24
Attack: 1 Bite +24, 2 claws +19, 2 wings +19, 1 Tail Slap +19 melee; Breath +24 ranged
Damage: 1 bite 2d6+6, 2 claws 1d8+3, 2 wings 1d6+3, 1 tail slap 1d8+9, Breath weapon 12d4 (23)
Special Attacks/Actions: Breath weapon, fear (DC 20), SR 18
Abilities: Str 23, Dex 10, Con 19, Int 12, Wis 13, Cha 12
Special Qualities: Acid immunity, water breathing, Darkness, orrupt water CL 3rd
Feats: #Feats: 7
Skills: Skill points: 25
Advancement: 20-21 HD (Huge)
Climate/Terrain: Any marsh and underground
Organization: solitary, pair, or family (1-2 and 2-5 offspring)
Treasure: Double Standard

Source: Monster Manual

Combat

Breath Weapon (Su): A black dragon has one type of breath weapon, a line of acid. 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. The black dragon's breath weapon deals 12d4 acid damage. Creatures caught in the area can attempt Reflex saves (DC 23) to take half damage.

Water Breathing (Ex): The dragon can breathe underwater indefinitely and can freely use its breath weapon, spells, and other abilities while submerged.

Corrupt Water (Sp): Once per day the dragon can stagnate 10 cubic feet of water, making it become still, foul, and unable to support animal life. The ability spoils liquids containing water. Magic items (such as potions) and items in a creature's possession must succeed at a Will save (DC20

Other Spell-Like Abilities: 3/day - darkness (radius 60 feet).

Water Subtype

This subtype usually is used for elementals and outsiders with a connection to the Elemental Plane of Water. Creatures with the water subtype always have swim speeds and can move in water without making Swim checks. A water creature can breathe underwater and usually can breathe air as well.