Snake-dogs were around 2 ft (0.6 m) tall at the shoulder, with an elongated body and a snake-like tail. Its body was about 4 ft (1.2 m) long and its neck the same length again. It has an elongated, flattened snake-like head except for the ears. The snake-dog can unhinge its own jaw to allow it to swallow larger objects than would normally fit, and has rows of sharp fangs. It is covered in snake-like jungle-coloured scales which help its disguise in a jungle environment.
The snake-dog is aggressive, but not overly so, fiercely protecting its own kind, especially females and the young. It is able to swim well thanks to its snake-like qualities, helping it through the water. It has a venomous bite which it will use in a confrontation, as well as the ability to trip bipeds using its long neck. They can be trained to become effective defensive pets.
Snake-dogs eat small rodents, mammals and vermin. The long neck helps it to capture prey inside burrows.
It was not clear whether or not it was a true descendant of the dog, but it is likely that they are the creation of a wizard rather than a natural evolution. Some of these snake-dogs also live in the Vilhon Reach area, again in yuan-ti company, but they do not survive in city-like environments, requiring moisture and water in which to swim regularly.