6. The Chestburster Scene - Alien
One of the main reasons for the continued regard for Ridley Scott's sci-fi masterpiece Alien is how shocking it continues to be to audiences young and old. Easily the film's most iconic moment comes when John Hurt's Kane is chest-bursted by the baby xenomorph, splattering the other crew members with blood before it scuttles off and transforms into the giant beast that stalks the gang for most of the film. If surprising the audience is one thing, Scott went one step further and decided to keep the cast in the dark as much as was humanly possible. Though they
did know the basic outline of the scene, they didn't know the litany of grotesque effects that were tied into the scene, such that when the blood begins to splatter over the crew members, their shocked reactions are completely authentic. Furthermore, Veronica Cartwright crying "Oh God!" was not scripted; she merely said it out of genuine shock, and Scott liked it so much he decided to keep it in the film.