Genuine disgust

One of the most iconic scenes in 'The Exorcist' is the vomit scene where a possessed Regan suddenly pukes on Father Damien Karras, and actor Jason Miller did not like making the sequence one bit.

In fact, the priest's disgust at being hit with sick was Miller's genuine reaction, as director William Friedkin started rolling without telling the actor.

The vomit itself was a mixture of oatmeal and Anderson's pea soup.