What are some REAL, scary movies?

Watch The Last Exorsism. I unfortuantely wet myself when I saw it. The Thing is pretty scary. The one where this alien is like a germ and while it digests of whatever living thing it ate, it mimics its form. There is IT. with Pennywise the dancing clown, I am now totally afraid of clowns. Those are NOTHING like Saw or those, they are more grueling, and bloody, but the suspense is wow!!! There is another movie where this virus gets into an apartment, and turnes people into cannibals, I would rate that 5 star scary.. i think it's called Quarentine.