Apparently there was a fad among video game manufacturers in the early 1980s... in which they all invested lots of money into making "promotional" robots http://flyers.arcade-museum.com/flyers_video/sega/16017701.jpg For the record Taito and Namco did this too. The difference there is that people actually bothered to photograph their works - I can't find a single piece of information about Sega Chan other than this flyer And just because there's a flyer doesn't mean these things were actually made and sold. Anyone ever spotted one of these in the wild?
Hello past self: https://archive.org/details/gamest0011/page/n40/mode/2up It only took 8 years but yes, here is a robot outside of Hi-Tech Sega Bashamichi in 1987. Quite a big thing. None of this has been translated. I assume it doesn't maul people on the street.