The Spanish slug is an air-breathing land slug. The size of the adult slug is 80 to 120 mm. Its color varies. It can be brownish or reddish brown, or brightly orange. The tentacles are usually darker.
The Spanish slug was first seen in 1954 in Great Britain. Nowadays, it is believed that the Spanish slug originated in southern France, from where it has spread through most of Europe.
Arion vulgaris inhabits areas that are moist, including deciduous forests and grasslands. However, the slug is often found in human-made habitats, such as gardens, parks, croplands, ditches, and wastelands.