Sergey Ponomarenko was found wandering the streets of Kyiv, Ukraine in April 2006. He claimed he was born in 1932 and lived in 1950 shortly before he was found by the police in 2006.
The mystery got weirder when the authorities started investigating and discovered that a man with the same name had been missing since 1958. The only photos offered as evidence of the strange event all come from a reconstruction made for a Ukrainian documentary series called "Aliens" that aired in 2012. There is no proof that any of this even happened.