4. Vladimir Demikhov
Soviet surgeon Vladimir Demikhov revealed his brilliant idea to the world in 1954. He was thinking of creating a two-headed dog where the head of puppy would be grafted onto the head of a grown German shepherd.
The second head would lap at milk even though it needed no nourishment. However, the milk would dribble down the neck since its oesophagus was disconnected.
Both animals died soon due to tissue rejection but this did not stop Vladimir Demikhov from creating nineteen other such dogs. If there was an award for the cruelest person he would definitely get it.