Are you sitting comfortably?
As I understand it two cars, technically called Autowelo type 650, were built by ex- Auto Union engineers for Stalin's son in Russia. They were 2litre V12s and bore a great similarity to the Pre-War Auto Union racing cars ie technically advanced - too advanced for the Russion engineers who received them and nicknamed them Sokols (falcons). A combination of Stalin's death, regime change and the inability to get them running reliably meant they were mothballed and kept at the EMW factory in Eisenach. There they were examined, experimented with - possibly by fitting one with a BMW 2litre engine, raced up an autobahn but not raced in anger. They were however used in a film called 'Rivals at the Wheel', and this is where one of them got the dummy bodywork.
Both cars still exist, one completely rebuilt by the Donington museum, and the other apparently incomplete but in Dresden.