So I am scrutinizing my tank last night, (as us aquarists tend to do) and I saw the freakiest thing I ever saw! I have a dead coral skeleton, rubble size that I stick different place to plug holes. I've had it in my tanks as long as I can remember. A week or so ago, I guess after I tweaked the rock work, I moved it up to the top under the skimmer spillway to plug a hole. I think the thing is sprouting!!! It sure looks like live tissue. I'll take a pic as soon as it gets a little bigger. I'm guessing the skeleton was a bird's nest but I'm not sure. We will see!