HD: 1-3 hp
AC: 5 
Attack: Bite 1-2 pts, claws 1-3 pts
Special: Venomous bite, climbing, camouflage
These shy, diminutive creatures are hunters and scavengers, about the size of a chihuahua, preying on any insect, reptile or mammal up to about the size of a rat, or feeding on the remains of any larger animals they may find. They are not particularly aggressive unless cornered, and will (if possible) flee from anything larger or more dangerous than their prey; if they attack a larger creature, it will be solely so that they can escape, and they will not persist if an escape route presents itself.
Their needle-like fangs can inflict deep puncture wounds, and the bite is venomous: a paralysing and necrotizing poison that numbs and eats away at the surrounding tissue, leaving it dead and gangrenous. A bite to a hand or foot will, over the course of a few Turns, will leave it numb, useless and stinking. A bite to the head or neck can easily kill the victim.
The adder-wyrm has gecko-like pads on its spatulate toes, allowing it to run up sheer surfaces and even across ceilings. Like a chameleon, it has an extensible tongue that it can use to attack flying insects and the like, and it can also change its colour to match its background — when motionless, an adder-wyrm can be quite difficult to detect.
The retiring nature of the adder-wyrm means that it usually presents no great threat to adventurers, but they will sometimes creep into a bag or pack in search of food, and may sometimes be surprised during the search of a chamber.
Adder-wyrms live in all sorts of environments short of arctic cold, and in the tropics they can become something of a pest, as they breed more successfully the warmer and more humid the climate. They are often found underground when food is plentiful.
Adder-wyrms make very poor pets, but might possibly serve as a wizard's familiar.