Prior to the release of the original PlayStation, Nintendo was working with Sony on an add-on for the Super Nintendo Entertainment System (SNES), which would have had support for CD-ROMs. Eventually, though, the partnership fell apart, leading Sony to create its own console, and making the Nintendo PlayStation one of the more interesting pieces of unreleased gaming hardware.
Only one working prototype of the console is known to exist, and it's been in the news a few times throughout the years. Most notably, in 2017, YouTuber Ben Heckendorn managed to repair the CD drive on the unit that had previously been unusable. Now, the functional prototype has been put up for sale on auction website Heritage Auctions, and the current highest bid is already $33,000.
Heritage attests that the prototype is working and that it was able to play Mortal Kombat on the system using a Super Famicom (the Japanese version of the SNES) cartridge. However, there is no known gaming software designed for the console's CD-ROM drive, so the only thing you can do with it is play music. Interestingly, though, the console itself has a small screen that displays which music track is being played, so you can actually play music from a CD while playing a game from a Super Famicon cartridge.
Heritage's description for the item also recounts the story of how this particular unit came to be discovered:
At one time, this particular unit was owned by the founder, first president, and first chief executive officer of Sony Computer Entertainment, Inc. Olaf Olafsson. Olaf eventually left Sony to join Advanta Corporation, and became its president in 1998. A little over a year later, Olaf left Advanta to join Time Warner -- but he left his Nintendo PlayStation prototype behind at Advanta. Roughly around this time, Advanta filed for bankruptcy and began gathering up everything in their corporate office to sell at auction. As the story goes, the Nintendo Play Station prototype was grouped together with some miscellaneous items that was boxed up with a group lot, the contents of which were veiled.
This series of events and coincidences is quite interesting all on its own, and without it, it's likely that this prototype would never have seen the light of day. If you're interested in owning a piece of gaming history and have a few thousand dollars to spare, you can check out the auction page.