From Kook Science

A transmigrant, or walk-in, is a possessing entity that takes over the physical body of a human host, sometimes for the rest of the life of the host; as distinguished from trance mediumship, where the host is temporarily usurped by the possessing entity, and reincarnation, where the soul is thought to pass from one life to another. Our use of the term is borrowed from William S. Burroughs, who wrote of a form of transmigration in his 1981 novel Cities of the Red Night.

By their own accounts

The following persons claimed to be transmigrants: