Not quite down the sidewalk on a leash (although the mess it would make on the neighbor’s lawn is too small to matter).
It’s actually a project for an engineering/development convention called Build 18 hosted by Carnegie Mellon University’s Electrical and Computer Engineering department. The device is just a little robot with motors and wheels, but the thing that controls the robot is a regular pet store goldfish. A camera senses where in the tank the fish is, either the front or rear, or left and right sides of the tank. Depending on where in the tank the fish swims, the robot move in that direction. Here’s the demo of the creation above.
No fish were harmed during the writing of this post.