At their most basic, movies within the body horror subgenre show the human body distorted in grotesque ways. But unlike subgenres like splatter, body horror is typically about transformation more than destruction (though destruction may be a byproduct of the process of transformation). Body horror movies are usually meant to elicit a feeling of revulsion in the viewer by playing on fears of physical vulnerability (which can tap into psychological horror). Sometimes bodies transform through natural or seemingly unnatural means, causing a character to feel uncomfortable in their own skin. Many body horror films also involve disease, parasites, infections, or some other invading force that plants itself within the body, mutating it from the inside. Movies like The Fly (1986) fit in to this category. Other times body horror is the result of an outside force, like a mad scientist modifying a person's body in horrific ways. The Human Centipede (2009) is an example of this.