Amaurobius ferox, sometimes known as the black lace-weaver, is a common nocturnal spider belonging to the family Amaurobiidae and genus Amaurobius. Its genus includes three subsocial species, A. fenestralis, A. similis and A. ferox, all three of which have highly developed subsocial organizations.

Females of this species range from around 11–16 mm in body length, while males are slightly smaller and more slender, ranging from 8–10 mm. The spider is very dark in color with its primary shades being black, brown, dark red, and tan. The abdomen is rounded and has light yellow pale markings in a unique pattern that is often described as resembling a skull-like mask or delicate skeletal pattern.

Amaurobius ferox is usually found near man-made structures. The species prefers dark areas, such as underneath logs or inside cellars, and it often likes to live in moist, shaded crevices including underneath stones or dilapidated walls. In the spring, adult males can likely be found indoors while they wander in search of mates, but adult females can be found indoors or outdoors at any time of the year.

Amaurobius ferox is native to Europe and is distributed across the continent, but it has been introduced into all three countries of North America, as well as some Eastern European countries such as Turkey. The spider is rare in Northern Europe where temperatures are too low for its survival.

Amaurobius ferox is known to spin a cribellate web to facilitate prey capture and provide a protective retreat. The web is special because the silk has a unique woolly texture that is caused by extremely thin and extraordinarily sticky fibers, which gives the species its common-name, the black lace-weaver. A. ferox prefers to lay its webs on vertical surfaces, and the species most often creates a tangled mesh of threads surrounding a circular retreat leading into a crevice. When the web is newly spun, it is extremely sticky and has a lace-like appearance and faint blue color. The web is most often spun at night due to the species' nocturnal activity, but they are known to respond to any insect prey that gets stuck in the web during any time of day.

In late summer and autumn, males wander in search of prospective females to mate with. Males often enter females’ webs and spin special silk threads to advertise their presence and attract the web's owner. Females lay their eggs in a white sac in a sheltered place, which she usually guards until the eggs have hatched. The egg sac is lens-shaped and ranges from about 7 to 15 mm in diameter. The egg sac contains anywhere from 60 to 180 eggs inside.

Females live for two years, while males only a few months.

The dispersal of A. ferox from the maternal nest does not occur at the same time for all the spiderlings within a clutch. A. ferox spiderlings disperse over an average period of one month, with half the clutch undergoing dispersal within the first three weeks. When half of a clutch is dispersed, remaining individuals are larger than those that dispersed.