Grooved brain coral, Diploria labyrinthiformis , with possible black band disease or another pathogen killing the very large living coral. If we don’t take care of our reefs, there won’t be any left. There are hundreds of years of growth in this picture.
Scientific classification Kingdom: Animalia
Phylum: Cnidaria
Class: Anthozoa
Subclass: Hexacorallia
Order: Scleractinia
Family: Faviidae