Renilla koellikeri is a sea pansy (order Pennatulacea, family Renillidae) found in shallow sandy habitats of the eastern Pacific coast, forming kidney-shaped or disc-like colonies anchored in soft sediments by a short peduncle with numerous feeding polyps covering the dorsal surface. Sea pansies are bioluminescent, producing flashes of light through a luciferase-based system using renillin as the luciferin substrate, and have been used in research on bioluminescence mechanisms. Genomic data have been generated for this species and are available in public databases, enabling comparative studies of cnidarian evolution and ecology.