Thanks for the comments all.
BTW, the rock has been in my tank for a couple months. These things surely came with the rock but had gotten to the rock at some prior point. I think the rock started off as dead 'live rock' and wasn't wild or aquacultured
So this particular spot on the rock is interesting because the circle around which these things are growing is black and scaly. It adds enough texture that the GHA in the picture are finding a point of attachment. The rock doesn't have GHA elsewhere on it.
Ron- Whatever it is, not knowing its name, is bugging me more than the thought of whether it will survive.
mcgyvr- This picture was taken with a phone and I will try a shot with another camera.
Crayola- I think my first thought was pineapple but pineapple sponges are more ovoid, sometimes 'fuzzy' and have defined filaments around the osculum. But, on the one hand, I don't think they are sponges because I don't see an osculum (opening), on the other I've sometimes failed to see that until the sponge grows more.
Crawlerman - You think I'm looking at pedal laceration from the neighboring ricordea? The thought crossed my mind but I dismissed it..
I think a better picture and time will help me ID this sucker.