The prototype that led to the launch of the original PlayStation back in 1994 was a hybrid console made in collaboration with Nintendo circa 1992. It is said that only 200 of these prototypes were made, and only one survived throughout the years. This fabled unicorn is now up for auction and could end up fetching upwards of US$2 million.
https://www.notebookcheck.net/Fabled-early-90s-Nintendo-Sony-PlayStation-console-prototype-goes-up-for-auction-could-fetch-more-than-US-1-2-million.453817.0.html