Now, police departments all over the country are responding.
Creepy clowns were spotted walking around Sheboygan, Wisconsin over the weekend. It was unknown Tuesday night if the knife was real or if the one clown was armed with a handgun.
The hysteria spread further this week with officials in California and OR forced to respond to numerous clown sightings - largely considered to be hoaxes - and social media threats against schools, also considered to be pranks.
Several people have posted about the clown sightings, which were allegedly concentrated in southwest Oklahoma City.
The bulletin confirmed a number of clown-related social media posts threatening violence at schools in Pennsylvania and other states had surfaced during the weekend.
"We go out to nursing homes and hospitals for people who are having a bad day or a tough time in their life", says Professor Dum Dum.
"Undoubtedly as Halloween approaches, we anticipate an uptick in clown sightings", the department said in a news release.
The nature of the threats was not revealed, and officials have not disclosed how many phone calls and social media posts they've received about such threats.
Since August, people in upstate NY and in states including South Carolina, Maryland, Pennsylvania and Georgia have reported scary or suspicious incidents involving people dressed as clowns.
The clown hysteria began in SC in August with multiple reports of clowns attempting to lure children into woods.
SC isn't the only state that has had clown sighting reports.
"People make them unsafe", she said.
The district has since interviewed all participants, and determined the clown sighting at Feist Park was a hoax and these individuals do not pose any threat to the campus.
It's an image that doesn't always sit well with a lot of people: clowns.
There have been no credible threats to any Dodge City schools.
The Lake County, Ohio Sheriff's office wrote on Facebook on Wednesday that the clown stories are "beginning to create alarm" among school children. Police said no one was attacked, chased or was in danger.