In terms of size, it can reach 15 cm. Its distinguishing characteristics are its black color, which can also be dark brown, its robust body with a smooth, viscous texture, and its antennae, which it uses for vision. Its thick, sticky mucus serves as defense and aids locomotion. It is mainly active on humid days, avoiding sunlight. During warmer days, it usually hides under stones, logs, and leaves.

It feeds on a wide variety of plant materials, such as leaves, fungi, and fruits, but also on decaying animals and plants. This is why it is a good decomposer, helping to recycle organic matter and improve soil fertility. It reproduces around spring and summer, laying its eggs in damp, sheltered places. This species is hermaphroditic, possessing both sexual organs; that is, each slug in the pair lays eggs. These take 3 to 5 weeks to hatch.