They are part of the phylum Cnidaria, in a class called Anthozoa or "flower animals".
[1][2] Brain corals extend their tentacles to catch food at night.
The surface is hard and offers good protection against fish or hurricanes.
The behavior of one of the most common genera, Favia, is semiaggressive; it will sting other corals with its extended sweeper tentacles during the night.
[3][4] The grooved surface of brain corals has been used by scientists to investigate methods of giving spherical wheels appropriate grip strength.