Scientists working for NASA have built a "variable gravity simulator" that is powerful enough to levitate a mouse. The device is made of a “superconducting magnet that generates a field powerful enough to levitate the water inside living animals.”
The study hopes to find a way to counteract bone loss due to reduced gravity over long spans of time, as in deep space missions.
Apparently, the mice quickly adapted to levitation and acted normally after 3-4 hours, even eating and drinking. The strong magnetic fields did not seem to have any negative impacts.