>Joseph Carey Merrick (5 August 1862 – 11 April 1890), often erroneously called John Merrick, was an English man with severe deformities. He was first exhibited at a freak show as the "Elephant Man", and then went to live at the London Hospital after he met Frederick Treves, subsequently becoming well known in London society.
At some time after the release of black and white 2, Junichi Masuda (the director of Game Freak) began having recurring nightmares about this man. On his twitter (since deleted), he would explode in rage at the thought of creating creatures that were ugly, like Mr. Merrick here. Since then, Masuda has "smoothened" all creatures in the pokemon universe, resulting in pokemon like Scorbunny over the "deformed" older creatures, like Nidoran. It's widely assumed that due to Masuda's hatred of anything not smooth and beautiful, he's culling the dex, so that the deformed creatures will never appear again.