It looks like a Trachyphyllia or commonly known as an "open" brain. This species can commonly be confused with other corals such as Scolymia(donut/meat coral). Shots of it closed as well as the mouth and oral disc would be helpful in a general identification, but for something very specific the skeleton would need to be analyzed, which none of us would like to do since it requires the corals death.
Very cool coral! Nice picture too!