Pale green ophidians with lidless, pupil-less eyes of ocher, they dwell in, under and among cactus in deserts bordering the most desolate of wastes. They have an array of keen senses, sight, heat and tremorsense that prevent them from ever being surprised. While they won't pursue travelers, they will quickly strike any who venture within reach. At night they will gather around the traveler, basking in his body heat during the chill of the night. Invariably, they let the sleeper awaken and realize their horrific predicament before sinking their fangs. Their poison is extremely virulent and the causes the most wracking pains during death.
All agree that the viper's only redeeming feature is that it is more merciful than what awaits the traveler in the wastes.
Inspiration: The Abominations of Yondo