Popular culture - from Batman's The Joker to Pennywise in Stephen King's It - suggests the children's party favourites give us something to fear. Now creepy clowns, lurking in dark corners, wielding the odd weapon, have closed schools, created mass panic and kept police officers in the US, UK and Australia busy.Rolling Stone magazine said the craze started on August 21, when a child in South Carolina told his mother that he saw a clown lingering in a wooded area near their home.The boy's older brother claimed the clown was rattling chains against their door, though their mother never saw a thing. No evidence was found to support the claim but their Greenville apartment complex quickly became a hot spot for clown sightings. Since then reports of clowns around neighbourhoods have filled up social feeds as imitators don their own masks.In his 1981 book Mysterious America, cryptozoologist Loren Coleman coined the phrase "Phantom Clown Theory", which refers to the way a few sightings of clowns "luring" children into vans, cars and forests can turn into mass hysteria - even though no clowns are ever actually caught.Speaking to Rolling Stone last week he said that, though this phenomenon has existed for more than 30 years, the recent spate has become more visible because of social media. In the UK, reported the Daily Mail, the craze has taken a dark and sinister turn after it emerged a boy of 17 suffered serious head wounds and a father was knifed in two separate incidents involving attackers disguised as circus pranksters.In Cumbria, north west England, it has taken a change for the strange, where a man is dressing as Batman and vowing to chase down the creepy clowns. A photograph has been shared on Facebook of "Batman" seemingly chasing off a killer clown.BBC Cumbria reported that local company Cumbria Superheroes is behind the effort to rid the streets of clowns. They have reassured viewers that the costumed man is not a vigilante, but is just trying to reassure local children who are scared of the "killer clowns".One police force in the UK had to deal with 14 clown-related incidents in 24 hours and police forces across the country have warned that incidents are accelerating...