Chaos Drives are cylindrical tubes that contain a varying amount of Chaos Energy. They look similar to lava lamps when full, the energy always seeming to alter between liquid, plasma, gas and electricity itself within. When nearing empty, the drive shows a more concentrated arc of electricity between the nodes on the top and bottom.
Chaos Drives power large amounts of Imperial machinery, and they were invented by Robotnik himself. Their ability to supply vast amounts of energy per unit makes them very valuable, but also volatile - if chaos energy is hit by a projectile(especially more chaos energy), the explosion will be quite violent.