Incrediscoly
A variant of Scolymia (Doughnut / Button Coral) (Homophyllia australis)

Photo: (c) Susan Prior, some rights reserved (CC BY) · CC BY
Representative Scolymia (Doughnut / Button Coral) image. A confirmed image of this exact morph isn't available yet.
A famous Homophyllia australis specimen from 2010, covered in a rainbow of coloured stripes.