Horror movies are meant for scaring us, however, sometimes the scenes are so real-life that they even terrify the crap out of the actors performing them.
Alien (1979)
Remember watching this classic horror movie? Then you’ll remember the scene in which THAT alien sprang out of the astronaut’s chest – only to scare the hell out of everyone, including the movie’s cast. The reason of the cast becoming truly horrified – as you can see for yourself in the scene – is that they were unknown of what was going to happen next.
Yes, they knew what the next scene was, but they weren’t aware that a worm alien – with all its guts and blood – was going to come out of John Hurt’s chest.  The scene was so breathtaking that actors performing it retreated to their rooms to get a breather and lower their blood pressure.
 
The Exorcist (1973)
In a documentary titled The Fear of God, the antics of William Friedkin has been brought to light as to how the film maker made The Exorcist look real. William refrigerated the room of where the exorcism took place to make sure that shivering was real. What’s more, he even kept randomly shooting artificial guns on the set to ensure that actors remained alert.
That said, it was the vomit scene where William used the best of her sadistic ability to horrify, in addition to the public, the cast of the movie. Jason Miller, the protagonist in the movie, was so pissed off at the vomit scene that after finishing it, he took the rest of the day off.
 
The Blair Witch Project (1999)
This movie revolves around friends who go on a camping trip which, as their ill-luck would have it, turns into a death trap for them. To make sure that the scenes look real, the director gave the cast members the necessary supplies – before leaving them to fend for themselves in the woods.
As a result, the movie contains scenes in which the actors were actually trying to find a way for themselves. After a few days passed, their food ration was cut down to make sure the actors became angry and ragged. Then when the actors were sleeping, the crew would appear from nowhere, to shake their tents and terrorize them.
 
The Departed (2006)
There’s one thing when you watch Jack Nicholson playing the role of a bad guy, it will only terrify you. Now, imagine that you’re the guy who’s right next to Nicholson in the scene, how will you feel when Jack, out of nowhere, starts taking out weapons.
DiCaprio felt one such moment of fear when, in The Departed, Jack felt that DiCaprio wasn’t scared enough to pull off the scene. Then, after consulting with the director, Jack Nicholson shoved a real handgun in the face of DiCaprio. And as Scorsese Confirmed, Leo was terrified big time.
 
The Texas Chainsaw Massacre (1974)
If there is one movie which shows how the work of a director could get the best – or crap – out of the performers, it has to be The Texas Chainsaw Massacre. For instance, during the scene in which Gunnar Hansen (Leatherface) hacks Allen Danziger (Jerry) to pieces, the cries of the latter were real because he hadn’t seen the mask before.
