2. Linda Blair (The Exorcist)
There really isn't anything more terrifying in the world of cinema than Linda Blair. No matter how many behind the scenes you may see, of a young Blair messing around in horrific make up, or having fun with her co stars in between takes, The Exorcist, and its child star are enough to evoke the fear of God in the strongest of cinema lovers. Blair's performance was famously dubbed by radio actress Mercedes McCambridge which arguably gives the film it the most unsettling edge, but for a child actress, the things Blair was even eluded to perform would make the most seasoned of actress blush. At a tender age of 13, so heinous was her acting that her first scene with seasoned actor Max Von Sydow was one that left him shaken and unable to remember his lines after Blair reeled off a tirade of abuse and swear ridden filth.