Non-human creatures. In horror films, these tend to kill people without reason or remorse.
It applies to any fictional creature, usually found in legends or horror fiction, that is often hideous and may produce fear or physical harm by either its appearance or its actions. The word “monster” derives from Latin monstrum, an aberrant occurrence, usually biological, that was taken as a sign that something was wrong within the natural order.
A Creature or Monster connotes something wrong or evil and is generally morally objectionable, physically or psychologically hideous, and/or a freak of nature. It can also be applied figuratively to a person with similar characteristics like a greedy person or a person who does horrible things.