Bay (Su): When a yeth hound howls or barks, all creatures except other evil outsiders within a 300-foot spread must succeed at a Will save (DC 12) or become panicked for 2d4 rounds. This is a sonic, mind-affecting fear effect. Whether or not the save is successful, an affected creature is immune to that hound's bay for one day.

Trip (Ex): A yeth hound that hits with its bite attack can attempt to trip the opponent as a free action without making a touch attack or provoking an attack of opportunity. If the attempt fails, the opponent cannot react to trip the yeth hound.

Flight (Su): A yeth hound can fly as the spell cast by an 11th-level sorcerer, as a free action. A yeth hound that loses this ability falls and can perform only partial actions.

Sonic Lance (Su): Every 2 rounds, an yrthak can focus sonic energy in a ray up to 60 feet long. This is a ranged touch attack that deals 6d6 points of damage to a single target.

Explosion (Su): The yrthak can fire its sonic lance at the ground, a large rock, a stone wall, or the like to create an explosion of shattered stone. This attack deals 2d6 points of piercing damage to all within 10 feet of the effect's center. This counts as a use of the sonic lance and thus is usable only once every 2 rounds, and never on a round following a sonic lance attack.

Snatch (Ex): An yrthak that hits a Medium-size or smaller creature with a claw attack attempts to start a grapple as a free action without provoking an attack of opportunity. If it gets a hold, it can fly off with its prey and deal automatic claw damage, though it prefers to drop victims from a height. It can drop a snatched creature as a free action, which deals normal falling damage if the yrthak is flying.

Blindsight (Ex): An yrthak can ascertain all foes within 120 feet. Beyond that range it is considered blinded. Yrthaks are invulnerable to gaze attacks, visual effects of spells such as illusions, and other attack forms that rely on sight. An yrthak whose sense of hearing is impaired is effectively blind, treating all targets as totally concealed.

Sonic Vulnerability (Ex): Yrthaks are affected by loud noises and sonic spells (such as ghost sound or silence) and are more susceptible to sound-based attacks, suffering a -2 racial penalty to all saves.

Spell-Like Abilities: 1/day-animal trance, cause fear, deeper darkness, entangle, neutralize poison, suggestion, and polymorph other. These abilities are as the spells cast by an 8th-level sorcerer (save DC 13 + spell level).

Psionics (Sp): All yuan-ti can produce the following effects at will:

• Detect Poison: As the spell cast by a 6th-level sorcerer.
• Alternate Form: The yuan-ti can assume the form of a Tiny to Large viper. This ability is similar to a shapchange spell cast by a 19th-level sorcerer but allows only viper forms. If the yuan-ti has a poisonous bite of its own, it uses its own or the viper's poison, whichever is more potent.
• Chameleon Power: The yuan-ti can change the coloration of itself and its equipment to match its surroundings.
• Produce Acid: The yuan-ti can exude acid from its body, dealing 1d6 points of damage to anything it touches. The acid becomes inert when it leaves the yuan-ti's body.
• Aversion: The yuan-ti creates a compulsion effect targeting one creature within 30 feet. The subject must succeed at a Will save (DC 17) or gain an aversion to snakes for 10 minutes. Affected subjects must stay at least 20 feet from any snake or yuan-ti, alive or dead; if already within 20 feet, they move away. A subject can overcome the compulsion by succeeding at another DC 17 Will save, but still suffers deep anxiety. This causes a -4 reduction to Dexterity until the effect wears off or the subject is no longer within 20 feet of a snake or yuan-ti. This ability is otherwise similar to antipathy as cast by a 16th-level sorcerer.

Halfblood Features (Ex): Yuanti halfbloods have certain snake-like features to their anatomy. Roll twice on the following list, ignoring duplicate or contradictory results:

• 1 - Snake head: Bite damage 1d6 and poison (save DC 14; initial and secondary damage 1d6 temporary Constitution)
• 2 - Flexible torso: +1 racial bonus to Reflex saves
• 3 - No legs, snake tail: Speed 20 ft., climb 15 ft., swim 15 ft; can constrict Medium-size or smaller creatures for 1d6+3 damage
• 4 - Snakes instead of arms: Gains 2 bite attacks (1d4 arms damage and poison as above)
• 5 - Scales instead of skin: +4 natural armor
• 6 - Legs and snake tail: Speed 30 ft., swim 15 ft.; can constrict Small or smaller creatures for 1d4+3 damage

Spell-Like Abilities: (If human-headed) 1/day-animal trance, cause fear, deeper darkness, entangle, neutralize poison, suggestion, and polymorph other. These abilities are as the spells cast by an 8th-level sorcerer (save DC 13 + spell level).

Psionics (Sp): All yuan-ti can produce the following effects at will:

• Detect Poison: As the spell cast by a 6th-level sorcerer.
• Alternate Form: The yuan-ti can assume the form of a Tiny to Large viper. This ability is similar to a shapchange spell cast by a 19th-level sorcerer but allows only viper forms. If the yuan-ti has a poisonous bite of its own, it uses its own or the viper's poison, whichever is more potent.
• Chameleon Power: The yuan-ti can change the coloration of itself and its equipment to match its surroundings.
• Produce Acid: The yuan-ti can exude acid from its body, dealing 1d6 points of damage to anything it touches. The acid becomes inert when it leaves the yuan-ti's body.
• Aversion: The yuan-ti creates a compulsion effect targeting one creature within 30 feet. The subject must succeed at a Will save (DC 17) or gain an aversion to snakes for 10 minutes. Affected subjects must stay at least 20 feet from any snake or yuan-ti, alive or dead; if already within 20 feet, they move away. A subject can overcome the compulsion by succeeding at another DC 17 Will save, but still suffers deep anxiety. This causes a -4 reduction to Dexterity until the effect wears off or the subject is no longer within 20 feet of a snake or yuan-ti. This ability is otherwise similar to antipathy as cast by a 16th-level sorcerer.

Poison (Ex): Halfbloods and abominations with snake heads only-bite, Fortitude save (DC 17); initial and secondary damage 1d6 temporary Constitution.

Improved Grab (Ex): To use this ability, a snake-headed abomination must hit with its bite attack. If it gets a hold, it can constrict.

Constrict (Ex): An abomination deals 1d6+6 points of damage with a successful grapple check (using the bite attack bonus if snake-headed) against Large or smaller creatures.

Spell-Like Abilities: (Human-headed) 1/day-animal trance, cause fear, deeper darkness, entangle, neutralize poison, suggestion, and polymorph other. These abilities are as the spells cast by an 8th-level sorcerer (save DC 13 + spell level).

Psionics (Sp): All yuan-ti can produce the following effects at will:

• Detect Poison: As the spell cast by a 6th-level sorcerer.
• Alternate Form: The yuan-ti can assume the form of a Tiny to Large viper. This ability is similar to a shapchange spell cast by a 19th-level sorcerer but allows only viper forms. If the yuan-ti has a poisonous bite of its own, it uses its own or the viper's poison, whichever is more potent.
• Chameleon Power: The yuan-ti can change the coloration of itself and its equipment to match its surroundings.
• Produce Acid: The yuan-ti can exude acid from its body, dealing 1d6 points of damage to anything it touches. The acid becomes inert when it leaves the yuan-ti's body.
• Aversion: The yuan-ti creates a compulsion effect targeting one creature within 30 feet. The subject must succeed at a Will save (DC 17) or gain an aversion to snakes for 10 minutes. Affected subjects must stay at least 20 feet from any snake or yuan-ti, alive or dead; if already within 20 feet, they move away. A subject can overcome the compulsion by succeeding at another DC 17 Will save, but still suffers deep anxiety. This causes a -4 reduction to Dexterity until the effect wears off or the subject is no longer within 20 feet of a snake or yuan-ti. This ability is otherwise similar to antipathy as cast by a 16th-level sorcerer.

Poison (Ex): Halfbloods and abominations with snake heads only-bite, Fortitude save (DC 17); initial and secondary damage 1d6 temporary Constitution.