Corporelectroscopy

Corporelectroscopy was the process by which two (or more) people switched their minds into each others' bodies. It could allow a brain to move into another individual's body, effectively taking control.

The Javaman, a scientist with considerable imagination, called corporelectroscopy a "scientific implausibility". He was unaware that the theta-waves emitted by his Dorganator had caused the process to occur with the Sixth Doctor and Peri Brown. The Doctor later told Peri that corporelectroscopy was dangerous knowledge, and that it was "best left to the Time Lords". (PROSE: Turnabout is Fair Play) This could explain their desire to stop Crozier whose mind-swapping would have upset the natural order of evolution. (TV: Mindwarp)

Coporelectroscopy may have been the process used to trap Kroagnon's brain in the basement of Paradise Towers, as he later "developed a means of performing" the process to transplant his brain into the Chief Caretaker. This presumably killed the Chief; additionally, Kroagnon walked stiffly and spoke as though his tounge was swollen, and the Chief's skin took on a silvery colour, and his moustache grew. (TV: Paradise Towers)