Scorpion, Mindkiller (CR 18)

Huge Undead
Alignment: Always neutral evil
Initiative: +4 (Improved Initiative); Senses: darkvision 60 ft., tremorsense 120 ft., Listen +1, and Spot +40

AC: 40 (-2 size, +32 natural), touch 8, flat-footed 40
Hit Dice: 32d12 (208 hp); DR: 15/good and silver
Fort +12, Ref +12, Will +21
Speed: 40 ft., climb 40 ft.
Space: 15 ft./15 ft.
Base Attack +16; Grapple +43
Attack: 2 claws +28 melee and 3 stings +26
Full Attack: 2 claws +28 melee and 3 stings +26
Damage: Claw 3d6+24/19-20; sting 1d10+9/19-20 plus poison
Special Attacks/Actions: Mindkilling aura (30 feet, DC 30 negates), constrict 3d6+19
Abilities: Str 48, Dex 10, Con -, Int 2, Wis 12, Cha 18
Special Qualities: fast healing 10; undead traits, obey the wormtouched
Feats: Ability Focus (poison); Cleave; Great Cleave; Great Fortitude; Improved Initiative; Improved Critical (claw; sting); Iron Will; Lightning Reflexes; Multiattack; Power Attack
Skills: Climb +31, Hide -4, Listen +1, and Spot +40
Advancement: 33-36 HD (Huge), 37-60 HD (Gargantuan), 61-96 HD (Colossal)
Climate/Terrain: Wormcrawl Fissure
Organization: Solitary, pair, or brood (3-6)
Treasure/Possessions: None

Source: Dungeon #134

Constrict (Ex): A mindkiller scorpion deals automatic claw damage on a successful grapple check.

Improved Grab (Ex): To use this ability, the mindkiller scorpion must hit with a claw attack.

Mindkilling Aura (Su): The mindkiller scorpion radiates an aura of madness and insanity that invades and ruins the minds of living creatures within 30 feet. Any such creature must make a DC 30 Will save each round it remains within this aura. Failure indicates the creature suffers 1d6 points of Intelligence, Wisdom, and Charisma drain. This is a mind-affecting effect.

Obey the Wormtouched (Ex): Although it is nearly mindless, a mindkiller scorpion unerringly follows simple commands given by other undead servants of Kyuss.

Poison (Su): Injury, Fortitude DC 32, initial damage confusion for 1 minute, secondary damage 3d6 Intelligence drain. The save DC is Charisma-based, and includes a +2 bonus from Ability Focus.

Skills: A mindkiller scorpion has a +4 racial bonus on Climb, Hide, and Spot checks.

In combat, the mindkiller seems to have a strange and unsettling knack for seeking out and focusing its attacks on the most intelligent living foe in the area. This is due to a rudimentary ability for the scorpion to "smell" intelligence - this ability isn't enough to grant it any actual game benefits, but does allow the relatively unintelligent undead to focus its wrath upon the smarter foes in its reach.