The Fears of a Clown.

Well slap my thigh and call my lady patch Audrey. New research has shown that children are scared bloody witless by clowns. Who'd a thunk it?
From the BBC

"Children are frightened by clown-themed decor in hospitals, a survey suggests. How did the smiley circus entertainers become a horror staple?
Anyone who has read Stephen King's It would probably never choose to decorate a children's ward with clowns.

And it probably comes as no surprise to horror fans that a University of Sheffield study of 250 children for a report on hospital design suggests the children find clown motifs "frightening and unknowable".

It is the fear of the mask, the fact that it doesn't change and is relentlessly comical


One might suspect that popular culture is to blame. In It, made into a television movie in 1990, Stephen King created a child-murdering monster that appeared as a demonic clown.

King's It has sparked a slew of schlocky movies over the past 20 years, known as the killer clown or evil clown genre.

Examples include Clownhouse from 1990 where three boys at home alone are menaced by escaped mental patients who have taken on the identities of clowns they have killed; Mr Jingles from 2006, where a killer clown takes its revenge; and 2004's In Fear of Clowns, in which an artist with coulrophobia is stalked by a clown resembling one of her paintings.

S.I.C.K., Killjoy and the Camp Blood Trilogy are other low-budget examples of the genre. But perhaps the highlight is 2001's Killer Klowns from Outer Space, with the tagline "In Space No One Can Eat Ice Cream"."

Yeah yeah yeah, I don't think we can blame Stephen King at all, the reason used Pennywise the clown in IT is because he ALREADY knew they were terrifying. Although King certainly amped up the terror. Between the wind resistant balloons and the razors in the gums and the 'We all float down here' eeeeeeeeeeeek, damn you king, I want MegRyanFish to cuddle in terror.
But clowns have always been frightening and I'm not a 100% sure why, even as a youth I remember going to the circus and being relieved when they went out of the ring, sure they're funny when doing pratfalls and what not, but the laughter was always slightly strained and fearful.
The paramour has two great fears, people hiding behind things and leaping out at him screaming 'RARRRGH' and clowns.
(There was/is a place in Barcelona called Tibidabo, it's a fun park, where you can be chased by midget clown with knives. I know personally of one strapping man who was a near gibbering wreck after such an encounter)
Children often don't find stuff as amusing as we adults thing they will. Beautifully made wooden toys for example. We buy them for their worthiness, hand craftiness and clunky cuteness. We present them, beautifully wrapped, to excited children who rip open the paper and then oh so politely thank us-as their parents have thought them to do- before they hurtle back into the living room to play with Girl's World or the bright yellow plastic Tonka truck someone else who actually understands children bought.
But children have this one nailed and I am totally in accord with the mini people.
Clowns are scary buggers, me no likey.
Clowns, I am against them.