As you can see, this is what my group and I have decided to use for the costume of the killer within our horror trailer. The concept was that the killer would be from the early 20th century, taking the form of someone who was involved in the first or second world war.
The large trench coat gives a very intimidating feeling because it is large and covers most of the persons body, making it appear he is very concealed and this can be a scary feature for a killer because the less the audience know, the more intrigued they are to figure out who it is.
The gas mask reflects the time period in which the killer comes from. It could possibly be ironic of the fact it is helping him breathe but he is trying to kill people and stop them breathing. The colour white is an important feature of the mask because it emphasizes that the killer is a complete blank and mysterious, leaving the audience curious as to what he may look like; there is no indication of his facial features, which effectively de-humanises him.