So-called “creepy clown” sightings have spread across more than 20 U.S. states and parts of Canada leading to arrests, school warnings and police investigations. And for Miles Leahy who has ...

While mysteries abound about the clowns, most incidents come in two forms: threats on social media, often directed at schools, or sightings of people dressed as clowns, some of which have turned ...

Given history's various episodes of mass hysteria, from UFO sightings to 2016's epidemic of clown sightings — remember those?