Summer sunlight flickers through warm waters off the coast of Spain. The sea looks calm and peaceful. Near the surface, invisible to the naked eye, a swarm of microscopic plankton, some orange-pink and others dark green, swims in lazy circles, capturing the sun’s rays and using the solar energy to make nutrients through photosynthesis. Suddenly, a tentacled creature called Mesodinium—at 22 microns, a giant next to some of the three-micron sun-gathering plankton—comes zigzagging through the waters, drawn by sugars and amino acids leaking from the smaller organisms. Its tentacles shoot out and engulf the hapless green prey, or nanoflagellates, which are completely consumed and digested.