Landwyrm, Underdark (CR 8)

Large Dragon
Alignment: Usually lawful evil
Initiative: +5; Senses: blindsense 60 ft.
Languages: Draconic, Undercommon, and Common

AC: 22 (-1 size, +1 Dex, +12 natural), touch 10, flat-footed 21
Hit Dice: 12d12+48 (126 hp)
Fort +12, Ref +9, Will +11
Speed: 60 ft., swim 30 ft.
Space: 10 ft./5 ft.
Base Attack +12; Grapple +20
Attack: Bite +15 melee; or claw +13 melee
Full Attack: Bite +15 melee and 2 claws +13 melee
Damage: Bite 2d6+4/19-20, claws 1d8+2 plus 1 Con
Special Attacks/Actions: Frightful presence, obscuring mist, wounding
Abilities: Str 19, Dex 12, Con 18, Int 13, Wis 17, Cha 16
Special Qualities:
Feats: Improved Critical (bite); Improved Initiative; Multiattack; Stealthy; Track
Skills: Bluff +14, Diplomacy +5, Escape Artist +12, Gather Information +5, Hide +9*, Intimidate +15, Jump +16, Knowledge (Underdark) +12, Knowledge (local) +7, Move Silently +200, Sense Motive +14, Survival +13, and Swim +4
Advancement: 13-19 HD (Large); 20-31 HD (Huge); 31-36 HD (Gargantuan)
Climate/Terrain: Underground
Organization: Solitary, pair, or clutch (3-6)
Treasure/Possessions: Standard

Source: Draconomicon

Blindsense (Ex): An Underdark landwyrm's extraordinary powers of scent and echolocation allow it to pinpoint the location of any living creature within 60 feet.

Frightful Presence (Ex): 60-ft. radius, HD 11 or fewer, Will DC 19 negates.

Obscuring Mist (Su): Three times per day an Underdark landwyrm can exhale a cloud of obscuring mist (as the spell, caster level equals landwyrm's HD).

Wounding (Ex): An Underdark landwyrm's claws deal bleeding wounds, similar to those caused by a wounding weapon. In addition to hit point damage, a claw attack deals 1 point of Constitution damage when it hits a creature. A critical hit does not multiply the Constitution damage. Creatures immune to critical hits are immune to this Constitution damage.

Skills: An underdark landwyrm has a +8 racial bonus on any Swim check 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. Underdark landwyrms have a +4 racial bonus on Move Silently checks. *hey have a +4 racial bonus on Hide checks when in rocky underground environments. This bonus on Hide checks increases to +8 when the landwyrm is immobile.