What do you think of when you think about clowns? Smiling painted faces pulling never-ending scarves from their mouths? Sad hobos with five o'clock shadow and patches on their clothes? Or maybe Robin Williams playing "Patch Adams," the doctor who believed in the powerful medicine of laughter.

Or how about this guy:

It
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Was the clown from Stephen King's "It" worse left to your imagination in the book or more terrifying brought to life in the movie?

The hatred for clowns runs so deeply that there has been a self-proclaimed "official anti-clown website since 1996," www.ihateclowns.com. Even children, who are supposed to love clowns, just don't. In 2008, a study in England polled 250 children between the ages of four and 16 and found that the majority of those asked disliked and even feared clowns, according to Smithsonian Magazine.

So what makes those jolly jokesters so sinister?

Clowns throughout history have been court jesters, harlequins, tricksters and buffoons. Pygmy clowns entertained Egyptian pharaohs in 2500 BCE, according to Smithsonian Magazine. Hopi Native Americans had clown-like characters that interrupted serious rituals with silly behavior. Ancient Rome had a series of slippery customers called stupidus. Court jesters gave comic relief to medieval Europe.

Director of Talent for Ringling Bros. and Barnum & Bailey Circus David Kiser told Smithsonian Magazine that clowns have always had a dark side. Clowns used their antics to reflect the ludicrous behavior of society and derived comedy from mania for food, drink and sex. "So in one way, the clown has always been an impish spirit... as he's kind of grown up, he's always been about fun, but part of that fun has been a bit of mischief," Kiser said, according to Smithsonian Magazine.

Joseph Grimaldi, arguably the first ancestor of the clown we know today, was very well known in the early 1800s. Grimaldi's wild antics on stage and feats of physical comedy became largely associated with him as an off-stage person, according to Smithsonian Magazine, but his life was far from a laugh. "He'd grown up with a tyrant of a stage father; he was prone to bouts of depression; his first wife died during childbirth; his son was an alcoholic clown who'd drank himself to death by age 31; and Grimaldi's physical gyrations, the leaps and tumbles and violent slapstick that had made him famous, left him in constant pain and prematurely disabled," wrote Smithsonian Magazine. "As Grimaldi himself joked, 'I am GRIM ALL DAY, but I make you laugh at night."'

Grimaldi died a penniless alcoholic in 1837, according to Smithsonian Magazine.

Clowns became part of growing circus acts, filling in the time between modern acrobats and tumblers with a throwback of jesters past, but the more time they had to fill, the crazier their antics got, according to Smithsonian Magazine. French literary critic Edmond de Goncourt wrote in 1876, "[T]he clown's art is now rather terrifying and full of anxiety and apprehension, their suicidal feats, their monstrous gesticulations and frenzied mimicry reminding one of the courtyard of a lunatic asylum."

Fast forward to the sad, Depression-era hobo clowns of America which eventually gave way for a bright time for clowns - the 1960s, according to Smithsonian Magazine. Clowns like Clarabell and Howdy Doody's sidekick enjoyed fame and adoration. Bozo the Clown hosted a show that had a 10-year wait for tickets, according to Smithsonian Magazine.

As Bozo made crowds laugh with fake flowers or pies in the face, a clown was besmirching the good name of giggle-makers everywhere: John Wayne Gacy, according to Smithsonian Magazine. Between 1972 and 1978, Gacy killed 35 men. His work as Pogo, the birthday clown, was complete contrast to his murderous reality. "You know... clowns can get away with murder," Gacy said before his arrest, according to Smithsonian Magazine.

The "Killer Clown" has previously been convicted of sexual assault and was permitted to work at children's birthday parties. If parents weren't worried about stranger danger and the face beneath the paint, they certainly were after Gacy.

Killer Klowns
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Killer Klowns From Outer Space is a movie that plays on coulrophobia... big time.

In 1952, Jimmy Stewart played a clown who would never take off his make-up in Cecil B. Demille's "The Greatest Show on Earth." Spoiler alert: Stewart's character was actually a murdering husband hiding out after killing his wife, according to Smithsonian Magazine.

By 1986, when Stephen King released his book-turned-movie "It," the public was pretty much freaked out by clowns. It didn't take much to shove imaginations into a clown car and push them over the edge.

Clown conventions (yes, there are such things) and other clown-related gatherings started to see declined attendance in the 2000s, according to Smithsonian Magazine. "You don't really see clowns in those kinds of safe, fun contexts anymore. You see them in movies and they're scary," Martin Antony, a professor of psychology at Ryerson University in Toronto, told Smithsonian Magazine. "Kids are not exposed in that kind of safe fun context as much as they used to be and the images in the media, the negative images, are still there."

So in an age of Krusty the Clown on "The Simpsons," are kids ever going to experience the joy of a grown man (or woman) wiping banana cream from their eyes?

Some studies say "yes" to the pie in the eye, like a study conducted in Italy and published in the January 2013 issue of the Journal of Health Psychology. Study findings indicated that children exposed to clowns before undergoing surgery had less anxiety about the procedure.

A 2011 study published in the Natural Medicine Journal suggested that "clown interventions" helped speed the recovery time of children with respiratory illnesses. "Up to this point most of the data on laughter and healing has focused on only immune function -- in particular the effect of laughter on allergic and autoimmune responses -- with very little if any measurement of effect on acute infectious illnesses," the study author wrote. "The results of this study suggest a wider application of humor and laughter to a wider range of medical conditions."

Maybe Patch Adams was really on to something.