The Omen. A classic horror movie about the spawn of satan on earth. This flick is considered to be another one of those "cursed" movies. The ghost haunting/horror movie Poltergeist being the #1 contender for the 'cursed' title.
A few examples:
(Note: Spoilers and scenes not for the faint of heart below!)
The movie is known for a number of disturbing scenes. Here are a couple of them:
1. The decapitation scene
2. And now, the scene you're all waiting for!:
Horror fans rejoice and SNAG THE T-SHIRT!