"Since the horror genre depends in large part upon the unknown, and since nearly three-quarters of the Earth's surface is covered in water, the ocean is a natural setting for horror movies.Sometimes, the horror is derived from the vast, unknowable, alien darkness of the ocean itself. In films such as The Deep and The Abyss, the ocean itself is the "monster." Sea monster movies differ from shark movies in that they are based on real-life creatures such as crabs, frogs, or octopi, but usually in an exaggerated and thus unreal form. Giant sea creatures of legend differ from great white sharks in that they are at least understood to be the stuff of nightmares rather than reality. (On this list, Sharktopus gets a pass for being half-shark not only because his half-octopus side redeems him.) With the context of these movies, sea monsters also differ from sharks in the sense that many of them emerge from the sea to launch their attacks on land." - creepycatalog.com
