On January 13, 1959, Russian scientist Vladimir Demikhov carried out one of the strangest and most controversial experiments in history when he created a two-headed dog.

After years of research, “surgical combination of two animals with the creation of a single circulation," Demikhov chose two different subjects, a German Shepard whom Demikhov named Brodyaga (tramp in Russian) and a smaller dog that he named Shavka.

The procedure would have Brodyaga as the host and Shavka would be the dog supplying the neck and head attached to the host.

After a day of recovery, the two-headed dog was in great shape, taking into consideration the previous 23 attempts.

The operation only took three and a half hours and after a day’s recovery, the two-headed dogs or to be more specific, both heads reclaimed their sense (hearing, smelling, seeing, feeling, and tasting).

Sadly, this two-headed dog lived only for 4 days due to a vein accidentally being damaged in the neck. If this accident would have not taken place, Demikhov said that the dog could have lived even up to 40 days.