Over the past couple of weeks, beachgoers in Argentina have been joined by a number of unwelcome companions: tens of thousands of shiny black beetles.

Miles of beach from Mar de Ajo to San Bernardo were covered in the bugs, each about the size of a fingertip, reports La Nacion. The beetles are born underground, and emerge after the rains to mate, dying soon after. Wind and waves may have pushed this particular group to the seashore. “It wasn’t possible to walk without stepping [on] them,” wrote Reddit user mypolarbear, who visited the beach recently.

According to La Nacion, a similar pileup happened in 2012, leaving beetles scattered over the suburbs of Buenos Aires. Despite apocalyptic theories being bandied around Twitter, such invasions are “nothing more than a huge orgiastic mating ceremony between insects that live only four days,” the outlet explained at that time. In other words, a completely natural dose of sex and death.

Every day, we track down a fleeting wonder—something amazing that’s only happening right now. Have a tip for us? Tell us about it! Send your temporary miracles to cara@atlasobscura.com.