Some of the very first films were shock cinema. “The Execution of Mary, Queen of Scots” is exact proof of this. It is the first known example of film editing for dramatic effect and, let’s just say, the movie was ahead of its time!
The Youtube clip puts it a little more tastefully than I did: “The 1st edit within a film, and also used for the purpose of a stop-motion effect. The Execution of Mary, Queen of Scots shows a blindfolded Mary being led to the execution block. The executioner raises his axe and an edit occurs during which the actress is replaced by a mannequin. The mannequin’s head is chopped off and the executioner holds it in the air as the film ends.”