Mega Drive Floppy Disk Drive
From Sega Retro
The Sega Mega Drive Floppy Disk Drive is an unreleased peripheral for the Sega Mega Drive allowing it to run 3.5-inch floppy disks. It was advertised extensively with earlier shots of the system, though was not put on sale for unknown reasons. It could be seen as a successor to the Master System Floppy Disk Drive, which also remained unreleased.
The floppy disk drive would have fit into the Mega Drive's expansion port, located on the right hand side of the system. This expansion port would later be used for the Sega Mega CD, and it is unlikely both could be used in conjunction with each other. Later prototypes had the text "FDD" printed in large golden letters on the top.
Though a floppy disk drive would bypass the Mega Drive, one would eventually see a release on the Sega Saturn.