That's the League of Electronic Musical Urban Robots (LEMUR) GuitarBot built created by Eric Singer and friends in 2002. It is a four-string MIDI-based instrument/robot with moving frets that can play some awesome riffs!
Check out the GuitarBot playing "Emergency Bot TV Theme" - yes it's an oldie, but still a goodie: Hit play or go to Link [YouTube] | LEMUR website - via shoeBlade, Thanks Alex!