Heway

This big, pale-white serpent has scales that, unlike the dry hide of most serpents, are slimy, toxic and constantly shedding. Big eyes suit its dim-light hunting, heat-sensing pits on the snout aid it at night, and its tongue can taste water up to 20 miles upwind, guiding it to likely hunting grounds.

A coward, it fights only when cornered and prefers weakened prey, though starvation may push it to stalk healthy animals. Its real weapon is water. Slipping into an oasis or well, it swims about for hours, slowly releasing poison throughout. Anyone who drinks must save vs. poison at +2; failure brings 30 damage within 3d6 minutes plus 1d6 hours of paralysis, while success still costs 15 points. Even survivors may die of thirst trying to reach other water. It is unaffected by its own toxin, which comes only from its skin and works only if swallowed, so touching one is safe. Its jaws are weak and its bite harmless.

Its stare hypnotizes: a creature failing a save vs. paralyzation follows it home to be eaten. It also uses the stare to freeze a threat for 1d6 turns while it slips away, and to take small game when no poisoned prey is available. Desert tribes and others who rely on clean water slay these snakes on sight, using missiles to stay clear of the stare.

Its lair is barely big enough for itself and a single carcass. A clever heway poisons a well, drags a big kill home, eats and digests until the water clears, and then poisons it again, repeating as long as its den stays hidden and catching small prey by stare in between. Heway shun one another except during the annual mating, when after the winter rains they journey to ancestral spawning grounds deep in the desert. The hatchlings get no care; the strongest eat the rest and crawl off seeking water.

An opportunist, it waits until animals have drunk and died before it feeds, and happily shares with jackals and other scavengers since a fouled well yields meat for all. It is most exposed traveling between wells, so it moves at night. Herds trample any heway they catch in the open by day, while hyenas and great cats tend to leave, since only their claws can kill it safely and biters often die.

Unscrupulous tribes hunt heway to poison enemy waterholes, usually using dead snakes because even a caged one's stare is dangerous; a dead snake's poison is half strength and saves get +4. Once the snake is gone, fouled water turns safe within 2d6 days, the time set by how quickly it is renewed: a small spring-fed oasis may clear in two days, a seldom-used well in two weeks.