This roe deer in a nature reserve in Italy was born with a genetic mutation that has left him with but one antler. His name is Unicorn.

From the AP:
The one-year-old Roe Deer – nicknamed ‘Unicorn” – was born in captivity in the research center’s park in the Tuscan town of Prato, near Florence, Gilberto Tozzi, director of the Center of Natural Sciences, said. He is believed to have been born with a genetic flaw; his twin has two horns.