The beginning of the end. Tear it all down, say a prayer, and start again.
Kidding! I have no clue, but also following. I have something SIMILAR, but I don't think the same on just 1 rock I will likely start a similar post once I have paid closer attention to it to offer a little more background on it.
I have them too. Looks pretty bad after a water change as sand gets stuck in their webs and it looks like Halloween lol. Haven't noticed it bothering anything yet. I only have a few sps though.
Best way to get rid of them is fill there tube with super glue, or when they are out producing there web, take your bone cutters and cut as far down and as fast as you can
I have them as well. Never bothered anything in my tank.
But just in case, since I am really getting into the world of SPS now, I should get a CBB as future insurance?
I pretty much found out the same. They're filter feeders and use the mucous to grab food and pull it back. Apparently Coris wrasse, copperbands, and even racoon butterflyfish will eat them. Also emerald crabs but apparently they'll develop a real taste for meat after they're done with these guys.
I have a melanarus wrasse already, so I'm not sure if the Coris will work.
Feed a bit less. Snap the tubes or crush them. I had those pretty bad. They got killed off by wrasse. They will irritate your coral eventually. Can also jam a pink or needle in there too. Get rid of em.