Sega · 1995–1995 · None — cancelled before release
A Genesis and 32X combined into one machine for under $200. Sega advertised it in 1995 and cancelled it that October, and the "prototype" in the photos was a non-working mock-up of wood and plastic.
The 32X add-on had given the Genesis a second life as a 32-bit machine, but it meant a tower of hardware: a console, a mushroom-shaped adapter on top and a second power supply. The Neptune was Sega's plan to tidy that up by combining the Genesis and the 32X into a single unit. It appeared in Sega Magazine as early as March 1995, and Sega's official 1995 product catalogue presented it as the "Genesis 32X System", with a planned retail price of under $200 and a release planned for the winter. It never arrived. In October 1995 Sega cancelled the Neptune, concerned that another piece of hardware would dilute its marketing focus on the Saturn, and that a sub-$200 hybrid would sit uncomfortably close to its own 32-bit console. By then the 32X itself was failing commercially, and the Saturn had launched in the West that May. The Neptune is often described as a prototype, but the unit shown in promotional material was a non-functional mock-up built from wood and plastic to illustrate the intended design. Its legend outlived it: in April 2001 Electronic Gaming Monthly ran an April Fools' story claiming Sega had discovered a warehouse of unsold Neptunes.