Which dragon is referred to as a worm, found in damp locations, has only vestigal wings and cannot fly, are serpentine, brown, dull red or greenish blue skin and eat rabbits, farm animals, fish?

The Knucker dwells in damp holes instead of caves. They are 30 feet long. They have vestigial wings and are brown, dull red or a greenish blue. Their skin is leathery and their head is small. The call is a low gurgling or a bark in the mating season. They eat small animals. On average, they live for 1200 years.

The Knucker uses its purple venom which is fifty times stronger than hydrochloric acid and can liquefy prey. They live in damp, deciduous woodland near rabbit warrens. They prefer to hoard household items rather than treasure. The eggs are in various shades of green for camouflage and their chicks are largely aquatic.