This story was originally published on The Conversation and appears here under a Creative Commons license. The scary clown has become a horror staple. Featuring Art the Clown as the main villain, Damien Leone’s new film Terrifier 2 is so gruesome that there are reports of viewers vomiting and passing out in the theater. And every Halloween, you’ll see vicious clowns stalking haunted house attractions or trick-or-treaters dressed as Pennywise, the evil clown from Stephen King’s It. It can be hard to imagine a time when clowns were regularly invited…