Vaath (CR 4)

Large Outsider
Alignment: Always neutral evil
Initiative: +8 (+4 Dex, +4 Improved Initiative); Senses: scent, Listen +13, and Spot +13

AC: 22 (-1 size, +4 Dex, +9 natural), touch 13, flat-footed 18
Hit Dice: 6d8+12 (39 hp); DR: 10/iron
Fort +7, Ref +9, Will +7
Speed: 40 ft.
Space: 5 ft./10 ft.
Base Attack +6; Grapple +5
Attack: 2 claws +8 melee and bite +3 melee
Full Attack: 2 claws +8 melee and bite +3 melee
Damage: Claw 1d6+3, bite 1d8+1 plus poison
Special Attacks/Actions: Burrow into flesh, improved grab, poison, telepathic sensory conduit
Abilities: Str 17, Dex 18, Con 14, Int 16, Wis 14, Cha 13
Special Qualities: SR 16
Feats: Alertness; Improved Initiative
Skills: Climb +12, Intimidate +10, Jump +12, Listen +13, Move Silently +12, Search +9, Spot +13, and Survival +9
Advancement: 7-13 HD (large); 14-27 HD (Huge)
Climate/Terrain: Any land and underground
Organization: Solitary, pair, or pack (3-8)
Treasure/Possessions: Standard

Source: Book of Vile Darkness

Burrow into Flesh (Ex): If the vaath has reduced its prey's Dexterity to 0 or established a hold on it, the vaath's mouth-ended tendril burrows into the creature's flesh. The tiny mouth chews its way through the victim, dealing 1d6 points of damage per round. After 1d4+1 rounds of burrow- ing, the tendril reaches a vital organ. Unless the vaath is killed or the victim receives healing, death comes 1d6+4 minutes later. Most victims survive long enough to watch their own intestines and organs disappear into the vaath's hungry maw.

Improved Grab (Ex): If a vaath hits a Medium-size or smaller opponent with a claw attack, it deals normal damage and attempts to start a grapple as a free action without provoking an attack of opportunity (grapple bonus +13). If it hits with a claw, it can also burrow into flesh. The vaath has the option to conduct the grapple normally, or simply use its claw to hold the opponent (-20 penalty on grapple check, but the vaath is not considered grappled). In either case, each successful grapple check it makes during successive rounds automatically deals claw damage.

Poison (Ex): The bite of the vaath carries a poison (Fort DC 15) meant to incapacitate foes so that the vaath can torment the creature before it perishes. The initial and secondary damage is the same (2d6 points of Dexterity damage).

Telepathic Sensory Conduit (Su): The vaath's only supernatural ability comes into play when its mouth-tendril has burrowed deep within its prey. When the vaath begins savoring the meat and organs of the creature, it telepathically transmits the sensation of taste (and its own enjoyment of it) to all within 20 feet-including the victim. All creatures are allowed a Will saving throw (DC 14) against this mind-affecting effect. Creatures that fail their saves take 1 point of Wisdom drain due to the horrific effect the devouring has on one's sanity. Victims that fail the Will save take 1d6 points of Wisdom drain, but that only matters if the victim survives. Creatures that regularly feed on the type of creature being devoured are immune to this effect. But no creature, not even another vaath, is immune to the horror of experiencing what its own entrails taste like.

Scent (Ex): Vaaths can detect approaching enemies, sniff out hidden foes, and track by sense of smell.