This big guy is Hippasteria muscipula! A species I just described last year! (here) It would seem to occur over a pretty wide depth range..from several hundreds to several THOUSANDS of meters!
They seem to be primarily predators on bamboo "corals" which are octocorals in the family Isididae.
Another closely related Hippasteria-like sea star which we've seen in the Hawaii region is the genus Evoplosoma.
We've seen plenty of examples of Evoplosoma feeding in the Atlantic as well as parts of the Pacific.
BUT that's not all! We've encountered multiple goniasterid species apparently feeding on coral!