Well, this gives me the heebie jeebies.

A massive swarm of mayflies erupted in Wisconsin this week in such high numbers that the cloud of bugs appeared on radar.

National Weather Service employees at the La Crosse, Wis. weather forecast station were reportedly stunned by the size of the swarm. A press release read in part, “The radar detected the flies about 8:45 pm, emanating from the [Mississippi] river (the source) with echo values similar to that of light-moderate rain (35-40 dBZ). With a general south-to-north wind flow above the surface, the mayflies quickly moved north once in the air.”

The swarm was so thick that the Star Tribune reports that the insects covered cars, buildings, and, yes, even some pedestrians in La Crosse, La Crescent, and Stoddard. The bugs also rendered visibility so poor that they were reported as the contributing factor in a three-car accident near Red Wing that left one person hospitalized. In 2012, the last time the bugs were this thick, snowplows were called out to clear their dead carcasses from the road.