Deathcoils resembled colossal snakes some 80 feet (24 meters) long. The scales were hard and slippery, primarily dark green in color with round, dark brown and black markings. The eyes of a deathcoil were yellow.
Deathcoils were cruel, cunning, and predatory serpents.
Deathcoils were very strong, and capable of both swimming and climbing despite their size. Additionally, they could breathe out a cloud of poisonous gas twice each day.
Deathcoils were more intelligent than mere animals, but not so intelligent as stories gave them credit for. Nonetheless, aside from their typical hunting strategy of constricting their prey to death, they were drag prey underwater to drown it, plan ambushes- even to the point of scattering treasure around good ambush points, and drive animals into ravines and over precipices. Some deathcoils were even known to sink boats in rivers, and then pin them to make a larder of drowned prey. They were also known to leave their home forests to prey on livestock in pens at night.
Deathcoils were known to live in temperate forests across Faerun, preferring the fringes where large plains-animals might stray into their hunting-grounds.
Deathcoils were obligate and voracious carnivores, eating any carrion and fresh meat they could find, including any other snakes and even other deathcoils. Because of this, they were strictly solitary except when mating; deathcoils attacked each other on sight unless one was much larger, in which case the smaller fled.
Furniture was sometimes made covered in deathcoil skin, but the dangers of hunting the beasts meant that only royalty or otherwise exceptionally wealthy people, like Calishite satraps, could own such pieces. Deathcoils skin was valued because it kept it supple sheen for centuries.