Yuan-ti abominations are monstrous serpent-like creatures possessed of both great intelligence and powerful magic.
Yuan-ti abominations resemble massive snakes, some 8 to 12 feet long and weighing approximately 200 to 300 pounds, with scale-covered humanoid arms. Their scale patterns seem variable according to tribe, but they all had the wedge-shaped heads distinctive of venomous snakes.
Abominations often use scimitars in melee combat. They also attack using their fangs, delivering a powerful poison. Abominations did not wear armor for their scales were more than enough to protect them.
Abominations possess various innate psionic abilities that make them deadly warriors: they can induce a severe aversion to snakes in any creature within 30 ft of them, forcing that creature to stay at least 20 ft from any snake they saw; they can produce acid to coat their scales, or change the color of their scales to match their surroundings; they can detect poison at will; and they can shapechange into the form of a viper of variable size.
