6 spoilers for the movie The Prestige

Borden is actually two persons - twins.

Angnier did the trick by cloning himself, than killing the clone (and maybe even original self).

Batman V Wolverine: Dawn of Cloneing

Christian Bale's aide is his twin brother, David Bowie makes Jackman a cloning machine

Twins living before the Double Mint Gum Commercials find work as magicians.

Borden had a twin double and one of them died and the other got to stay with his kid.