Back in the early 1980's, the public got burned by Atari. Atari, Coleco, Mattel, and several others flooded the market with video games. Atari's greatest crime was making first party games with no quality. E.T., anyone? Because of this, anyone over the age of 18 back in those days never wanted to see another video game again.
Then came Nintendo.
Nintendo's own Famicom was doing well in Japan, and thought they could partner with Atari to bring it to the states. But something went awry with the deal, and Atari imploded. Nintendo decided to market the machine themselves, but they had a difficult road ahead of them. How could the sell video games to a public that has been burnt out on them?
Nintendo needed to market their machine differently. It was not a video game console, it was an Entertainment System. They weren't cartidges, they were Game Paks. But how could Nintendo convince Americans to buy Donkey Kong when they've bought it already? Maybe Donkey Kong isn't the answer. No, Nintendo had to be smarter than that. They used a robot.
The robot was sold in Japan as the Family Robot. Nintendo felt he could be marketed in America as R.O.B., the Robotic Operating Buddy. R.O.B. worked for two games: Gyromite and Stack-Up, and each game had different attachments for R.O.B. to work with while the game played. R.O.B. would see flashes on the screen and act accordingly. For it's time, R.O.B. was a fun addition to any game system. Did Atari have a robot? Did Coleco? No!
However, the novelty would soon wear off. R.O.B. ate batteries and wasn't all that effective. When all was said and done, R.O.B. soon outlived its usefulness when Mario came bounding along, and R.O.B. couldn't help with Koopas and Goombas. R.O.B. was a novelty act. But he did do his job, which was to sell the NES. After that, R.O.B. was gone.
These days, R.O.B. makes odd cameos in games like Star Fox, Startropics, Mario Kart, among others. He's also unlockable as a hat in the Mii StreetPass Plaza on the 3DS. He's also highly collectable, as many things in the era. If you have a R.O.B., he makes a great ornamental piece.