Iconography is an important aspect of genre. We expect to see certain objects/props on screen when we see a particular genre, for example, in a Western, dusty lonely roads, saloon bars, cowboy hats and horses, jails, sheriffs badges, guns, etc.
In a modern horror film, we expect young, vulnerable girls, ‘normal’ objects, use of darkness and the light, etc. These ‘genre indicators’ are called the iconography of the mise-en-scene or genre.
For a Supernatural Horror film, we would expect to see at least 1 Supernatural entity, as well as a fairly large, dark, abandoned house. These things have become normal, and expected us as it has always been this/that way. The first successful supernatural horror films must have used these things, inspired other supernatural horror films afterwards to do the same. Overtime, these things just become expected.
Here are some supernatural movie film titles. Each one had a supernatural entity, and a fairly large building in the background. The use of darkness is also in line with what is to be expected of a supernatural horror film.