Coulrophobia for fun
These days the major western folk-demons are Vampires, Werewolves and Clowns. The first two have a steady tradition, moon garlic graves silverbullet pointysticks yadda yadda, largely patched up by Hollywood from bits of folklore and Stoker, but they seem okay with it. But clowns are starved of back-story - Monday morning, they're happy serial killers, Tuesday lunch they're aliens in fright wigs and by Thursday they're Tim Curry down a storm-drain prattling about buoyancy. Justice demands they be given their own consistent mythos.

"They grow from the garish-colored fungi infesting lost cellars and evil woods. A dead clown should be burned; if buried, the fungi will grow from its grave, and any who eat this will die of it and rise from their own graves as clowns. In the day clowns hide from the sun in garbage bins and the larger kinds of postbox; at night they fall on travellers, paralysing them with pies of poison custard, and make them into sausages. They feed on the blood of their victims, stored in their bloated nose-bladders. Their cold hollow laughter corrodes mind and soul.

The only true defense is to gather one's courage and laugh back at them, for they have no true sense of humor and will burst and die from rage at human mockery. For this purpose the institution of Circus was created, in which men dress as clowns and perform absurdities so as teach us mirth in the face of these monsters."