SickSack (Sounds like Zig Zag).
Guess what? It's a robot. Yes, follows a black line on the floor like a snake. It has been designed by two innovative guys, Lars Pontoppidan and Aske Olsson in USA.
Click the link, http://pontoppidan.info/lars/index.php?proj=sicksack for more details about the robot. Don't forget to check out the videos.
It has been my dream for quite some time now, to do some work-around in Robotics. Hope it would work out some day.