Linnorm, Gray (CR 20)

Huge Dragon
Alignment: Usually chaotic evil
Initiative: +0; Senses: keen senses, Listen +22, and Spot +22
Languages: Draconic and Abyssal

AC: 27 (-2 size, +19 natural), touch 8, flat-footed 27
Hit Dice: 13d12+65 (149 hp); DR: 15/magic
Fort +13, Ref +8, Will +10
Speed: 30 ft., fly 90 ft. (good), swim 30 ft.
Space: 15 ft./10 ft.
Base Attack +13; Grapple +28
Attack: Bite +18 melee and 2 claws +16 melee and tail slap +16 melee
Full Attack: Bite +18 melee and 2 claws +16 melee and tail slap +16 melee
Damage: Bite 2d6+7, claw 2d8+3, tail slap 2d6+10 plus poison
Special Attacks/Actions: Breath weapon, crush 2d8+10, poison, spell-like abilities, spells
Abilities: Str 24, Dex 11, Con 20, Int 14, Wis 19, Cha 17
Special Qualities: immunities, SR 31
Feats: Alertness; Flyby Attack; Multiattack; Snatch
Skills: Bluff +19, Concentration +21, Diplomacy +7, Intimidate +5, Knowledge (arcana) +18, Listen +22, Search +18, Sense Motive +20, Spellcraft +20, Spot +22, and Swim +15
Advancement: 14-18 HD (Huge)
Climate/Terrain: Any hills or mountains
Organization: Solitary
Treasure/Possessions: Standard

Source: Monster Manual II

Acid Breath (Su): A gray linnorm can breathe caustic slime in either a 50-foot cone or a 100-foot line. This attack deals 6d8 points of acid damage, or half that amount on a successful Reflex save (DC 21). On a failed save, the slime also eats away the target's non-magical metal weapons and armor, making them useless in 1d6+5 rounds. Using a breath weapon is a standard action. Once a linnorm breathes, it must wait 1d4 rounds before using a breath weapon again. A blast from a breath weapon always starts at the linnorm's mouth and extends in a direction of its choice, with an area as noted in the description. At the time of use, the linnorm can choose to shape its breath weapon into either a 100 ft. line or a 50 ft. cone. Lines are always 5 feet high and 5 feet wide, and cones areas high and wide as they are long.

Poison (Ex): The tip of a gray linnorm's tail carries a venomous stinger that delivers its poison (Fortitude save DC 21) with each successful tail slap attack. The initial damage is 1d6 points of Constitution damage, and the secondary damage is 2d6 points of Constitution damage.

Spell-Like Abilities: At will - fly, protection from arrows; 3/day - contagion, meld into stone, wind walk. Caster level 17th; save DC 13 + spell level.

Spells: A gray linnorm can cast divine spells as a 17th level cleric. It has access to spells from the Destruction and Evil domains (spells/day 6/6/6/6/6/4/4/3/2/1; save DC 14 + spell level).

Feats: A creature that is flung by a gray linnorm after being snatched travels 70 feet and takes 7d6 points of damage. If the gray linnorm is flying, the creature takes this damage or the appropriate falling damage, whichever is greater.

Crush (Ex): A flying linnorm can land on opponents three or more size categories smaller than itself as a standard action. A crush attack affects as many creatures as can fit under the linnorm's body. Each creature in the affected area must succeed at a Reflex save (DC 21) or be pinned, automatically taking the given amount of bludgeoning damage. Thereafter, if the linnorm chooses to maintain the pin, treat it as a normal grapple attack. While pinned, the opponent takes crush damage each round.

Tail Sweep: A linnorm can sweep with its tail as a standard action. The sweep affects creatures four or more size categories smaller than the linnorm within a 20-foot-radius half-circle centered on the linnorm's rear. Each affected creature that fails a Reflex save (DC 21) takes the given amount of damage; a successful save halves the damage.

Blindsight (Ex): A linnorm can ascertain its surroundings by non-visual means (mostly hearing and scent, but also by noticing vibration and other environmental clues. This ability enables it to discern objects and creatures within 120 feet. A linnorm usually does not need to make Spot or Listen checks to notice creatures within range its blindsight.

Immunities: A linnorm is immune to sleep and paralysis effects.

Keen Senses (Ex): A linnorm sees four times as well human in low-light conditions and twice as well in norm light. It also has darkvision with a range of 120 feet.