Neptune

The 32X add-on for the Mega Drive/Genesis was rather expensive when it first came out, and did not see as much success as Sega hoped for. In order to make the 32X games more popular, it was believed that by combining the base unit (Mega Drive/Genesis) with the add-on (32X), the games would prove more popular. The combination of the two systems was called the Neptune, but it never saw production. Sega believed that when the Mega Drive/Genesis was ending its lifespan and the Saturn was on its way, the system would not prove popular enough to recoup costs.