Lukinrats

Please forgive the crappy pictures, but I tried to make the problem spots stand out a little easier.
So I have seen some spots on this coral that are white, and I have just been keeping an eye on it. The other day while inspecting closely with some magnification, I noticed that around some of the spots, there are these lesion looking things.
I can't figure out what could be doing this, unless it is a hermit crab. I had one that liked to climb all over this coral, and then sit in one ...