A blueberry slug is a species of slug native to most of California, Nevada, Oregon, and Arizona. It is a herbivore that mainly feeds on decaying vegetation, fruits, vegetables, grass, leaves, shrubs, bushes, mosses, and lichens. Unlike most slug species, they have thicker heat-proof skin, which helps keep the slugs alive, even in the hottest days as well as the driest in their native range, so it is common to see blueberry slugs in a field and other places even if the day is hot. It is basically a slug that resembles a banana slug, in which it is very closely related to, but is blue rather than yellow (which is how the blueberry slug got its name). Since it's bright blue, it has to be poisonous to almost all predators that try to eat it. Because of its toxicity, most predators will leave the slug alone, but the only predators that are immune to its poison are the American common dylanus as well as their domestic relative (the Domestic dylanus), so they can eat the blueberry slug without any harmful side effects occurring to the dylanuses. It is found in not just in forests, but also in grasslands, swamps, and even in human settlements, where they are considered as pests. They were also accidentally introduced to Florida, England, and Hawaii, where they are considered as among the 100 worst invasive species.