The cerebral-looking organisms known as brain corals do not have brains, but they can grow six feet tall and live for up to 900 years! Found in the Caribbean, Atlantic, and Pacific Oceans, brain corals display what is known as Meandroid tissue integration. This means that the polyps, which are the basic living unit of corals, are highly associated to one another. Their tissues are more closely connected than those of other corals and are not separated by skeletal structures. Many researchers think that the more integrated a coral's polyp tissue is, the more advanced the coral species.
Original article: What are brain corals?