Horror film openings

In my previous postings I focused more on what makes a horror scene, in general, effective, so I felt like I should do some research on what makes a horror opening specifically good.  From what I have discovered, it seems that there are 2 main approaches to opening up a horror film. You can either start off slow and create a rising tension or start off intensely and immediately grasp the viewers attention. 

One of the most well known and praised film openings in horror is from the movie Jaws by Steven Spielberg.  Throughout the entire opening, the shark is never fully shown once. Despite this, the opening is able to establish the shark as something violent and ruthless while at the same time building tension. Combined, they serve to create a very stressful and fear inducing scene that sets up an expectation for the audience for the remainder of the film.

                                                                            "Jaws" 1975

    This is another thing I feel that I can use to my advantage while making my opening. If I can find a way to establish my antagonist but not directly reveal them, this could help me to not only build suspense, but it also extends the possibilities of what my antagonist could be