This video shows a water flea playing with what appears to be a ball.
The flea (Daphnia) was caught poking around the volvox, a type of spherical green algae, in a video that took third place at the 2011 Nikon Small World in Motion competition. Researcher Dr. Ralf Wagner took this video with an electron microscope. Water fleas live in swamps, lakes and most aquatic environments where they eat algae, bacteria and other small organisms. According to the video, they also play with their food.