Adult Carpathian Blue Slug slowly moving on the forest floor.

Bielzia coerulans , Commonly known as the Carpathian blue slug or simply the blue slug , is a species of very large country slug , a terrestrial pulmonate gastropod in the family Limacidae , the keelback slugs. Inhabits deciduous and coniferous forests in mountains Benthic, usually at the bottom, or under deadwood logs.