A body swap is a storytelling device seen in a variety of fiction, in which two people (or beings) exchange minds and end up in each other's bodies. In media such as television and film, the device is an opportunity for two actors to temporarily play each other's characters, although in some cases, dialogue is dubbed by the original actors.
There are different types of body swapping. For non-technology swapping, switches can be caused by magic items such as amulets, heartfelt wishes, or just strange quirks of the universe. The switches typically reverse after the subjects have expanded their world views, gained a new appreciation for each other's troubles by literally "walking in another's shoes" and/or caused sufficient amounts of farce. Notable examples include the books Vice Versa (1882) andFreaky Friday (1972), as well as the film versions of both.
Switches accomplished by technology, exempting gadgets advanced sufficiently to appear as magic, are the fare of mad scientists. Body-swapping devices are characterized by highly experimental status, straps, helmets with complicated cables that run to a central system and a tendency to direly before their effects can be reversed. Those without such means may resort to brain transplants. Such experiments can have overtones of horror; evil mad scientists seldom use willing test subjects.
Since the Vice Versa novel was published in 1882, body swaps have been a popular theme in various media: