This is a manifestation of the Meissner Effect. When a superconductor reaches a critical temperature (usually very cold, 1 - 70 K) it expels all magnetic field lines. So if you place it on top of a magnet, it will float. It will float on a cushion of magnetic field. Additionally it will experience almost no friction so if you make a circular track of magnets it will levitate around it for quite a long time. And look awesome doing it. That vapour trail isn’t propulsive. It’s just how cold that superconductor is, it’s condensing the air around it.