They can be used as cautionary tales. By showing the negative consequences of body invasion, such as in a story where a character's body is taken over against their will, it can highlight the importance of having control over one's own body.
In some fantasy literature, there could be magic spells or curses that seem to 'invade' a character's body in the sense of changing their physical or mental state. This is often used to create tension and drive the plot forward as the character has to struggle against this unwanted intrusion.
Also, body invasion stories can sometimes cross the line into promoting harmful or non - consensual behaviors. Writers need to be aware of this and use these themes to raise awareness about the wrongness of such actions rather than glorifying them. For example, in a science - fiction context where a body is invaded by an alien force, it can be used to explore the horror and wrongness of having one's self - control taken away.
Typically, there is a protagonist who first notices the strange changes happening around him. But I can't recall the exact name from the top of my head. There are also the people who are being 'snatched' and turned into these strange replicas.
Well, the main theme is about the invasion of an unknown force that takes over people's bodies. It's a horror - themed concept that plays on our fears of not being in control of our own physical form and also reflects on the idea of how society can change and lose its humanity if something insidious creeps in.
A body swap sex story could start with two people who are complete opposites in terms of gender and personality. Due to some unexplained phenomenon, their bodies are swapped. The story could be about how they adapt to their new bodies. They might discover things about the opposite sex that they never knew before. For instance, they could find out about the different ways society treats the two genders. It's important to note that this should be a story that promotes understanding rather than focusing on improper aspects.