Scientists have found what is thought to be the first example of a two-headed reptile in the fossil record.
The abnormal animal, belonging to a group of aquatic reptiles, was unearthed in northeastern China and dates to the time of the dinosaurs. [...] This animal was a choristoderan, an extinct reptile that reached a length of one metre in adulthood and was characterised by a long neck - two in this case.
The animal's spinal column divided in two at the point where the neck emerges from the body. This formed two long necks that ended in two skulls.
It's all quite amazing and what I suspect will be a unique find (especially considering how difficult fossilisation actually is).