Krynickillus melanocephalus is a species of air-breathing land slug, a terrestrial gastropod mollusc in the family Agriolimacidae.

The species resembles in form other agriolimacid slugs (notably Deroceras), so has the pneumostome in the rear half of the mantle and a tapering tail without a marked keel.

The most distinctive feature is the deep black tentacles, head, and nape, with the dark colouration still visible under the front of the mantle.

The congener Krynickillus urbanskii (Wiktor, 1971), occurring in Romania, Bulgaria and Turkey, has a paler black head and a pale nape.

Although it has sometimes been reported as a pest of crops, others have suggested that a diet of algae, fallen fruit, and fungi makes it less of a threat.