Growth on my zoa - need help identifying

[pdt7361]

Hello group. I have noticed a disk shaped growth on the side of one of my small groups of zoas. The disk is almost a half inch diameter and is very solid/hard. The zoas were bought a couple of weeks ago and while we didn't notice it at the store, we have noticed it every since having them at home.
I captured a pic of it from the front and from the side...any thoughts?

 

[makeshift101]

Spirorbid worms, harmless

 

[pdt7361]

I wasn't referring to just the little white dots...the whole mass that those dots are on too.