Type “why are clowns scary?” into Google and the results are mixed and many. An Insider report in 2018 claimed it’s their unpredictability that terrifies, while on Quora, contributors aligned the fear of clowns (known as coulrophobia) with the theory of the uncanny valley, the point at which the subtly familiar and the alien overlap. Stare into the face of a clown and you see the constituent parts of a face, but it’s not quite human. It’s this unknowability that intimidates.

Clowns have often been used in film as protagonists of terror, perhaps most famously in the 1990 TV adaptation of Mr Stephen King’s It, in which Pennywise the Dancing Clown was made flesh with vaudeville flourish by Mr Tim Curry. Pennywise leapt from small screens to cinemas in 2017 in the first of a big-budget, two-part blockbuster, and clowns became shapes of the popular imagination again. Ahead of the release of part two this week, here are five other classic cinematic clowns that give us the heebie-jeebies.

Saw featured a miniature clown on a tricycle, who stood in for the hermetic baddie as the film’s axis of evil. But Jigsaw wasn’t a conventional-looking clown; more a Burning Man anarcho with a penchant for tailoring and juggalo make-up. His motives weren’t usual, either. He punished his victims by forcing them to inflict pain on themselves or others in order to test their will to live. As the film was inevitably franchised after the success of the original, Jigsaw became a modern horror icon.

The most notable thing about the clown toy in Mr David Fincher’s The Game is that, for once, it isn’t an object of fear. The figure, which is fitted with a secret camera to film Mr Michael Douglas, serves to introduce a feeling of mania to the film’s thriller narrative as the hero starts down a Homerian urban odyssey. There’s something about the clown’s fixed glare as it broadcasts footage of Mr Douglas back to him on TV that feels at once nihilistic and curious.

Freaks is horrible partly because it came out of nowhere. Sure, Germany had introduced some macabre figures to the masses in the wake of the silent movie boom – most notably the shrivelled Dr Caligari – but nothing, nothing like this. Cue self-castration, legless human chickens and living torsos, the kind of ensemble that would make even Mr Hieronymus Bosch blink. At the centre of the freak pie is Phroso the clown, whose whistling obliviousness adds a strange gravity to the horror around him.

That Mr John Wayne Gacy lured kids in Chicago to their deaths dressed as a clown called Pogo in real life always felt stranger than fiction. In 2003, no one really wanted a dramatisation of these killings, but in time, Mr Clive Saunders’ Gacy became an underground on-demand hit. Blame Mr Mark Holton, whose sweaty, twitchy protagonist casts a frost over the true-crime film. Before Gacy, Mr Holton played an adult bully in Pee-Wee’s Big Adventure. Both are characters whose arrested development pushed them over the edge.

Poltergeist has simple but classic set-up: boy sees a menacing clown at the end of his bed amid a wave of psychoactive disturbances in his home, the clown disappears, only to emerge with long, elastic arms craned to kill. Mr Tobe Hooper’s 1982 classic turned a suburban home into a Machiavellian fun house after the inhabitants of a burial ground the house was built on come back to life. It was undeniably the clown – an object of trust that becomes weaponised by the evil spirits – that rattled cinema seats the hardest.