This begins the last wave of MMII conversions. It's the weakest of the linnorms, which are really cool monsters that got crippled by having ridiculously low Hit Dice for their Challenge Rating. The linnorm below (same CR) had 13 HD in the original! Hopefully, these are closer to the mark.
Gray Linnorm
Huge Dragon
Hit Dice: 23d12+184 (333 hp)
Initiative: +4
Speed: 40ft (8 squares), swim 40ft
Armor Class: 38 (-2 size, +40 natural), touch 8, flat-footed 38
Base Attack/Grapple: +23/+43
Attack: Bite +33 melee (3d6+12)
Full Attack: Bite +33 melee (3d6+12), 2 claws +31 melee (2d8+6) and tail sting +31 melee (2d6+12 plus poison)
Space/Reach: 15ft/10ft (15ft with bite and tail)
Special Attacks: Breath weapon, crush 2d8+18, poison, spell-like abilities, spells
Special Qualities: Blindsense 120ft, DR 15/magic and good, immunity to sleep effects and paralysis, keen senses, SR 31
Saves: Fort +21, Ref +13, Will +19
Abilities: Str 35, Dex 11, Con 27, Int 16, Wis 22, Cha 20
Skills: Bluff +31, Concentration +34, Diplomacy +9, Intimidate +33, Knowledge (arcana) +29, Listen +34, Search +29, Sense Motive +32, Spellcraft +29, Spot +34, Swim +20
Feats: Alertness, Awesome Blow, Flyby Attack, Improved Bull’s Rush, Improved Initiative, Multiattack, Power Attack, Snatch
Environment: Any hills or mountains
Organization: Solitary
Challenge Rating: 20
Treasure: Standard
Alignment: Usually chaotic evil
Advancement: 24-46 HD (Huge), 47-69 HD (Gargantuan)
Level Adjustment: -
An immense gray-scaled serpentine creature slithers into view, the front of its body held above the ground. Its two clawed arms twitch as if anticipating an attack, as does its sinuous tail, tipped with a long ivory barb. The creature’s head is like that of a dragon, but its eyes are crazed with madness and bloodlust.
Linnorms are primeval creatures, possibly the progenitors of the draconic races. Gray linnorms are one of the weakest and smallest varieties, but are still large and strong enough to lay waste to entire countries. Their most admirable trait is their rarity.
Gray linnorms are inherently psychopaths. Although intelligent and cunning, they seem incapable of viewing other intelligent life as anything but playthings, food, and victims. These three terms are synonymous. Most gray linnorms establish wide territories, lairing in a cave at the top of a mountain or hill and considering all the land they can see as their domain. Any creature passing through their domain is a trespasser, and therefore entitled to be tormented, killed and eaten by the linnorm. Most linnorm territories are, therefore, desolate wastelands, or at the very least uninhabited.
Although other linnorms sometimes use their forelimbs for locomotion, gray linnorms refuse to dirty their hands this way. Talented spellcasters capable of tapping the primal power of destruction, gray linnorms would rather use their claws for the weaving of magic.
The average gray linnorm is nearly 50 feet long. They speak Abyssal and Draconic.
Combat
Gray linnorms do not have the patience for subtle tactics. When they spot an opponent, they use their overland flight or wind walk abilities to intercept the foe, casting protective or enhancement spells along the way. They open combat with a blast of potent acid, then close into melee. They would rather flee and plot revenge than die in a futile assault, and so use their spell-like abilities for escape purposes.
A gray linnorm’s natural weapons and any weapons it wields act as magic and evil weapons for the purposes of overcoming damage reduction.
Breath Weapon (Su): A gray linnorm can breath caustic slime in either a 100ft line or a 50ft cone, as it desires. All creatures in the area of effect must make a Reflex save (DC 29 half) or take 15d8 acid damage. The metal armor and weapons of creatures caught in the breath weapon dissolve and become useless they succeed on DC 29 Reflex saves. The save DC is Constitution based. Once a gray linnorm uses its breath weapon, it must wait 1d4 rounds before using it again.
Crush (Ex): This special attack allows a flying or jumping gray linnorm to land on opponents as a standard action, using its whole body to crush them. Crush attacks are effective only against Tiny or smaller opponents (though it can attempt normal overrun or grapple attacks against larger opponents).
A crush attack affects as many creatures as can fit under the dragon’s body. Creatures in the affected area must succeed on a Reflex save (DC 29) or be pinned, automatically taking 2d8+18 bludgeoning damage during the next round unless the dragon moves off them. If the dragon chooses to maintain the pin, treat it as a normal grapple attack. Pinned opponents take damage from the crush each round if they don’t escape. The save DC is Constitution based.
Poison (Ex): The tail sting of a gray linnorm injects a lethal toxin, causing excruciating pain, liquefying organs and eventually killing the opponent. Fortitude DC 29 negates, initial damage 2d6 Con, secondary damage 4d6 Con. The save DC is Constitution based.
Spell-like Abilities: At will – overland flight; 3/day – meld into stone, wind walk; 1/day – shapechange. Caster level 20th.
Spells: Gray linnorms can cast divine spells as if they were 17th level clerics. A gray linnorm has access to the following domains: Chaos, Destruction, Evil, Strength or War.
Typical cleric spells prepared (6/8/8/7/7/6/6/4/3/2; save DC 16 + spell level): 0th – detect magic (x2), guidance, read magic, resistance (x2); 1st – bane (x2), comprehend languages, divine favor, doom, entropic shield, protection from good*, shield of faith; 2nd – bear’s endurance, bull’s strength (x2), cure moderate wounds, death knell, resist energy, shatter*, spiritual weapon; 3rd – bestow curse (x2), blindness/deafness, contagion*, cure serious wounds, dispel magic, invisibility purge; 4th – death ward, divination, divine power, freedom of movement, spell immunity, tongues, unholy blight*; 5th – dispel good*, flame strike, greater command, insect plague, righteous might, true seeing; 6th – antilife shell, blade barrier, greater dispel magic, harm*, heal; 7th – blasphemy, disintegrate*, ethereal jaunt, repulsion; 8th – earthquake*, greater spell immunity, unholy aura; 9th – energy drain, implosion*.
* Domain spell. Domains: Destruction and Evil
Keen Senses (Ex): A gray linnorm sees four times as well as a human in low-light and twice as well in normal light. It also has darkvision to a range of 120ft.
Skills: A gray linnorm has a +8 racial bonus on any Swim check made to perform some special action or avoid a hazard. It can always choose to take 10 on a Swim check, even if distracted or endangered. It can use the run action while swimming, provided it swims in a straight line.
Demiurge out.