Garnet Hertz’ Cockroach Controlled Mobile Robot.

Garnet has this to say about his RoachBot:

"Cockroach Controlled Mobile Robot" is an experimental mechanism that uses a living Madagascan hissing cockroach atop a modified trackball to control a three-wheeled robot. If the cockroach moves left, the robot moves left. Infrared sensors also provide navigation feedback to the cockroach, striving to create a pseudo-intelligent system with the cockroach as the CPU.

Link (via Make and Reality Carnival)