Recently picked one of these up, it's a Tokima Steamhead made in 1998 by Bandai. It's kind of a re-invention of the kids watch they put out in 1983 called the Digirobo, which was plastic - and smaller. This watch is huge and heavy and, as you can see in the pics, it detaches from the frame to turn into a robot.
It also has over 800 messages programmed into it that scroll across the screen every few minutes. Most are in Japanese so I have no idea what they say, LOL.
The robot can be detached from the frame to use as a sort of desk clock and besides - he's pretty nifty looking.
The Steamhead is fairly heavy and wears big and folks generally notice it and comment on it. I've found it's kind of a 'love it or hate it' watch. Most people seem to like it. The one thing that's hard to get used to is how high it sits on the wrist - the watch is over 35mm high. Here's a pic next to the Revman, DW-6400 and WW-5300: