Monsters from Outer Space and the Deep
Monsters are pushed farther and farther from the center of the map with our every advancement. However, we still believe firmly that they are possible and that they exist "out there" somewhere. Now, monstrosity exists in outer space, and at the depths of the oceans -- the only two places that have yet to be fully explored by humanity. We can still believe that monsters exist there, because as it has always been, we simply do not know what is out there. The vast emptiness of space and the darkness at the bottom of the sea allows us to populate it with our wildest imaginations. The human imagination can be a quite overactive thing, and we fill this void with our concepts of monstrosity.
There have been many films treating with both concerns about outer space and the deep sea. Perhaps the most influential and commercially successful within each horror genre are Ridley Scott's Alien, and Steven Spielberg's Jaws, respectively. Both of these films were groundbreaking in many ways. They both set a new standard for special effects and the visual representation of monstrosity onscreen.
In Jaws, Spielberg generates suspense through not knowing where the monster is at any time. It is rarely seen, or only pieces of it are seen, allowing the viewer's imagination to run wild. The gigantic shark exists only as a spectre that the viewer knows is out there, but that it cannot fully comphrehend or picture. There have been a number of remakes and spinoff films that have attempted to emulate the success of the original film including 1999's Deep Blue Sea, 2003's Open Water, 2016's The Shallows, and 2018's The Meg. However, the vast majority of these have fallen short of the influential status and sheer terror of the original.
In Alien, darkness, flashing lights and other effects partially hide the creature from view for the majority of the film, again allowing the viewer to populate the space with their imagination. Interestingly enough, Alien drew largely upon the commercial success of Jaws when it was produced, having even been originally pitched by its producers as "Jaws in space". Alien, however, has arguably passed Jaws as one of the most influential films of all time for a number of reasons. Sigourney Weaver's character, Ripley, proved to be one of the first female horror protagonists and heroines.
The alien itself, was groundbreaking as well. The alien is represented as a "monstrous mother" (Creed). There are numerous undertones of sexualization and rape, as the alien forcibly penetrates its victims and parasitically uses them as a host for its progeny. There are references to the monstrous body and to monstrous reproduction throughout the film. Rather than simply being an influence upon, it essentially "spawned" the body-horror genre of monstrosity, a multi-film series that has been incredibly commercially successful at the box office, and dozens of look-alike films that have been released over the last thirty or so years.