The creepy clown terror that's stalking the nation has reached the edge of the Philadelphia region.

Pottsville police say they're investigating an incident where two suspicious clowns were seen yelling at children Monday evening. The male clowns - one dressed in orange, the other in black - could face charges of harassment and disorderly conduct.

The men were gone when police arrived, Chief Richard Wojciechowsky said. They fled in a gray or silver pickup truck. Meanwhile, farther west, state police in Huntingdon County said they too were investigating reports of a suspicious clown in the area. No description was available.

Those are the latest in what has become a disturbing parade of clown sightings across the country, from California to Indiana to points south, and this week in Annapolis, Md., where several children reported seeing scary clowns in what has now been declared a hoax.

No one has been injured. But people have been creeped out. And authorities take the calls seriously.

Several children in South Carolina last month said that clowns were offering them money to follow them into the woods. Some schools in Alabama saw increased security after clowns, or people hiding behind the image, made internet threats.

It's unclear how many sightings are copy cat clowns, pranks, or marketing ploys.

But fear of clowns is so common that it actually has a name: coulrophobia, the prefix from the ancient Greek, meaning "stilt-walker."

Even Stephen King has weighed in on the sightings, telling the Bangor Daily News that "kids love clowns, but they also fear them; clowns with their white faces and red lips are so different and so grotesque."

It's exactly that appearance, said Alex Skolnick, an assistant professor of psychology at St. Joseph's University, that can make clowns disturbing.

"The creepiness aspect has to do with clowns having exaggerated features," he said. "They're 'not right' humans."

These clowns also are appearing out of context, he said, showing up on downtown streets or near woodlands, strangely divorced from circuses or parties where they might be expected.

Efforts to contact several Philadelphia-area clowns for comment on the phenomena were unsuccessful.

In the Pottsville sighting, about 7 p.m. Monday, police got a report that two clowns were shouting at a group of children. The clowns wore no masks, showed no weapons, and made no attempt to harm the youths, police said.

"We have not received any other complaints of activity even remotely similar to this," Chief Wojciechowsky said. "If the intent was to scare children it was a callous and cowardly act. If it was more of a juvenile prank, it was a very bad decision."