A prototype of the Sony and Nintendo-developed PlayStation console which played both CD-ROM discs and Super Nintendo (SNES) cartridges has apparently been discovered. Pictures of the device have been shared on Imgur and Reddit (the page for which is currently down due to an ongoing drama).
The owner of the device (Imgur user DanDiebold) came forward on the Assembler Games forum to answer some questions. He says the device belonged to his father, who once worked alongside a Nintendo employee and happened across it in a box of junk after his company went bankrupt.
The user hasn't had the opportunity to boot up the device yet as he doesn't have the correct power cord, so he doesn't yet know what is on an unmarked CD and cartridge which came with the apparent prototype. He also intends to open the device up and take photos of the circuitry inside.
It has not been officially verified that the device is a genuine prototype, but it certainly appears that it is.
In the late 80s and early 90s Nintendo and Sony formed a partnership to create a CD-ROM-reading peripheral for the Super Nintendo called SNES-CD. Nintendo and Sony clashed over licensing arrangements which gave Sony more control over software licensing than Nintendo liked.
In May 1991 the device called the Play Station (space intended) was introduced at the Consumer Electronics Show, but the very next day Nintendo announced an ill-fated partnership with Sony rival Phillips. Apparently only 200 prototypes of the Play Station were made.
At the heart of all this was Ken Kutaragi, who forged ahead with the CD-ROM technology, leading to the original PlayStation (PSone) we know today, which launched in Japan in 1994 and cemented itself in video gaming history.