Takara Tomy earlier this year released a new line of miniature walking robots called ROBO-Q. They are billed as the world’s smallest consumer robot standing at 3.5 cm tall.
The robot is slightly bigger than a 100 Yen coin or about the size of your thumb. They can be remotely controlled and charged. The charge lasts for about 3 minutes of walking time.
Here is a good link to more info from botjunkie.com:
Japan has long had a reputation for miniaturization in electronics. This is another good example of that skill in a toy that retails for about 3,600 Yen.