In 2025, Limacus maculatus (Kaleniczenko, 1851) slugs were discovered within the city of Izhevsk, UdmurtRepublic. The specimens were found in a large ravine with a spruce forest and a meadow. This record represents thenortheasternmost known population of L. maculatus on the Russian Plain. The colonization of this semi-natural biotopeunderscores the species' high adaptive potential and indicates a capacity for further range expansion. This findingdemonstrates that L. maculatus successfully overwinters even in northeastern Europe and can colonize both forest andmeadow habitats. To date, known populations of L. maculatus in cities across the Russian Plain have been confined toanthropogenic shelters such as greenhouses, conservatories, and building basements. Consequently, the species has beenclassified as a domestizoid, i.e. a species restricted to human-made structures. The discovery of a population of L. maculatusin a minimally disturbed spruce forest within an extensive urban ravine fundamentally alters the author’s perception of itsdispersal capabilities. It is evident that the species' naturalization in the natural and semi-natural forests and meadows acrossmany regions of the Russian Plain is merely a matter of time. Therefore, based on this evidence, L. maculatus should bereclassified as an epecozoid – a species that has successfully colonized anthropogenic biotopes and continues to expand itsrange into new habitats. This case exemplifies not only the invasion of an alien species but also a dynamic shift in itsecological status within biogeocenoses. The research conducted under both field and laboratory conditions revealed notablevariability in the coloration of adult and juvenile L. maculatus. The general body color ranges from brownish-black tolighter brown, adorned with irregular spots and sinuous, light-brown lines. The mantle exhibits a brown or dark olive colorwith irregular olive spots. The reproductive system morphology is typical for the species. Egg clutches contain 31-32 eggs,a characteristic number for the genus Limacus Lehmann, 1864. The eggs are connected by thin mucous filaments, forminga distinct necklace-like structure. L. maculatus feeds on a wide range of vegetable and berry crops, marking it as potentiallydangerous agricultural pest. L. maculatus's ability to consume ruderal grasses and lichens ensures its survival andpersistence in anthropogenic biocenoses.