Millions of flightless insects, better known as Mormon cockroaches, have invaded part of Nevada, alarming residents, blanketing streets and buildings, and fueling nightmares. Footage posted on social media and local news shows six counties in the state under siege, with thick carpets of insects slowly moving across the state. A spokesperson for Northeastern Nevada Regional Hospital said a local hospital had to deploy brooms and leaf outlets to make way for patients to enter the building. Not only do insects conjure up plague-like images, but they also make roads dangerous when large numbers of them are squashed making the asphalt slippery.

Despite their name, the insects are not biologically crickets but technically large, shield-backed insects resembling grasshoppers, according to the University of Nevada. They do not fly, but walk or jump. They lay eggs in the summer that lie dormant in the winter and then hatch in the spring. But this year, due to an unusually rainy winter, the little ones arrived too late. The army of insects moving through Nevada can stay at its peak for four to six years, before being recaptured by other insects and predators.