I found these on clearance at Wal-Mart for like $2 a piece, I think. At the time I had a cat, so I bought two of them - one for him to play with and one for me to keep.
The mouse just sits there quietly until it hears a noise or feels movement, like when the cat meows or paws it. Then it will scurry about, flashing it's eyes and calls out to the cat to chase it. After 15 seconds, it will stop and wait until the cat attacks it again.
A very simple robot, to be sure, but in my opinion a robot nonetheless...
Year Released: ???
Dimensions: 1½" tall x 3" wide x 7" long