Is this a starfish?

[Wrothgar]

So I noticed something that came in on my torch Coral. After he closed up for the evening I saw a formation that looks strikingly like a star thought it was just maybe the way he had built his structure however the next day it was not there. I have now found this guy again after many months, all the way over here on my barrel display next to my montipora. Have I acquiesced a free starfish? or is this the coral eater monster 3k?

He's much bigger now.

 

[TX_REEF]

looks like an asterina starfish to me. They do not eat coral as far as I'm aware.

 

[JayM]

Looks like an Asterina starfish. Some say great clean up crew, some say coral eating monster. I had one in my tank for months with no issues until one day it was caught munching zoas. It got yanked quickly after that.