A major red tide event occurred in waters off Southern California in the spring of 2020, resulting in dazzling displays of bioluminescence along the coast. Now, for the first time, a study has pinpointed how the plankton species Lingulodinium polyedra — a dinoflagellate — was able to create such an exceptionally dense bloom. The answer lies in dinoflagellates’ remarkable ability to swim, which lends them a competitive advantage over other species of phytoplankton.