THE FLAGELLUM OF A BACTERIA
These are another incredibly complicated yet minute mechanisms that many bacteria possess. The flagellum is spun around by a rotating wheel just on the surface of the bacteria. It has all the parts that a modern electrical motor has - shaft, bushes, stator, rotors etc. The spinning of the curved flagellum acts like a propellor, pushing water to the rear and thrusting itself along.
Bacterial are supposed to be "primitive", yet they are equipped with these sophisticated devices to move them through their surroundings. Human attempts to build micro-motors are colossal and crude by comparison with these exquisitely designed mechanisms for locomotion found in so-called "simple" bacteria.