The first horror movie I ever saw was Halloween 2... I wasn't supposed to watch but I snuck into the back of the living room while the adults watched... and I don't think I blinked for 2 hours.
A mask that was actual a William Shatner mask, became the face of slasher films. In real time I didn't even notice that with each movie the mask changed. Now that I am older and I go back and watch, not only does it change... in some movies it's pretty ridiculous.
Check out the story behind all the mask changes... Click Here