California grunion are a species of marine fish found primarily along the coast of Southern California and Northern Baja California. They are justifiably famous for their unique spawning behavior. Grunion spawn completely out of the water and lay their eggs on many sandy beaches in California. Shortly after high tide, on specific nights, sections of these beaches sometimes are covered with thousands of grunion dancing about on the sand. The popularity of these grunion runs means that some nights there are more people lining the beaches than grunion in the run. (Source)
