Clown masks, ranging from cheery to evil, are displayed at the Fantasy Costumes HDQ store in Chicago prior to Halloween.

Tim Boyle/Getty Images

With tufts of multicolored hair, greasepaint grins and comically large shoes, clowns are the epitome of a carefree good time. At least for some people.

Others say clowns are no laughing matter. Instead of causing mirth at birthday parties or hilarity at three-ring circuses, the feelings clowns evoke are at the other end of the spectrum. In fact, the sight of jolly buffoons performing their comedic shtick can be cause for fear and alarm.

At its most severe, this irrational fear of clowns -- known as coulrophobia -- can make people cry, scream or get angry. It also can prompt bouts of perspiration, nausea and rapid heartbeat. The fear probably stems from the uncomfortable sense of disconnect between watching a character in gleeful disguise while his true identity and emotions remain hidden [source: Briggs]. One psychologist estimated about 2 percent of adults experience coulrophobia [source: Rodriguez McRobbie].

The rate is probably higher for children. One survey of kids ages 4 to 16 discovered most of the 250 participants didn't like to view clown images, even when they were told the pictures were being considered as decoration for a hospital's children's ward. Some kids even feared the images [source: Rodriguez McRobbie].

Turns out these wary instincts are not without cause, at least from a historical perspective. While modern clowns are meant to entertain, their predecessors sported an ancient and sketchy past filled with maniacal behavior, infidelity, suicidal feats and murder.

It's a legacy so etched in our collective consciousness, it may cause the clown profession to become nearly extinct. Although professional clowning reached its peak in the early to mid-1900s, by the late 1960s, there were fewer than 200 professional circus clowns on record in the U.S. To combat these flagging numbers, Ringling Bros. and Barnum & Bailey opened a clown college in 1968. The actual school closed down in 1997, and now seminars are given throughout the U.S. for potential circus employees. However, other clown colleges exist, including the Dell'Arte International School of Physical Theatre in Blue Lake, California, and the International School of Theatre Jacques Lecoq in Paris [sources: Ringling, The Humour Foundation].

Nevertheless, the World Clown Association says membership has dropped from 3,500 in 2004 to 2,500 in 2014. Lack of interest among younger people, older clowns passing away and higher standards from employers are to blame, say association members [source: Musumeci].

But maybe it's also coulrophobia and the prevalence of the "scary clown" image that has led to slippage.