Spanish slug

The Spanish slug (Arion vulgaris, but formerly widely referred to as Arion lusitanicus owing to a misidentification) is an air-breathing land slug, a terrestrial pulmonate gastropod mollusk in the family Arionidae, the roundback slugs. Other vernacular names are Lusitanian slug, Iberian slug, and killer slug.

It is a large, conspicuous slug, which has spread across much of Europe since the 1950s and now reached North America. It may attain high densities and be a serious horticultural and agricultural pest, and is considered an invasive species. The life cycle is annual, with adults appearing in summer and dying off before winter.