An all in one Megadrive and Sega CD combo (similar to what NEC did with the Turbo Duo.) The American release of this console is the JVC X'Eye. Although rather expensive (retail: $620) the machine did a lot of stuff besides play games. This console had a visualsation program from music cds (a big deal in 1993,) also built in Midi capabilites allowed users to attach any Midi device along with keyboards and additional software to create thier own music. And since this is the Japanese we're talking about there of course was a built in Karaoke function.
Stuff like this never seemed to sell well in the U.S, as most stores didn't carry them because they could make more money if somebody bought a Genesis and Sega CD separately. There are also Victor and JVC Wondermegas which are a lot rarer than the Sega version and nowadays sell for upwards of $400.