Fears of a clown

Professional clowns complained that the current craze for scaring people by dressing in clown outfits was damaging their trade. But why do some people find clowns frightening?
— The effect was analysed in 1970 by Japanese professor Masahiro Mori as he researched robot faces. He found that the more lifelike faces induced increasing feelings of empathy until a critical point, at which point people began to find them scary.