I’ve been told that it’s just Xenia but it seems to kill coral. Thoughts? Suggestions on solution or just get rid of rock? Thanks, y’all!
Can you get a picture with more white lighting? It doesn't look like xenia to me, but hydroids could be a possibility.
At first glance that looks like aiptasia! However, when I blew it up the tentacles seem to have a "toothed" appearance. Aiptasia appear smooth IME. If you could get a closer picture (or use the one I blew up above) post it on the hitch hiker thread on Reef2reef and tag @KJ. He's the hitch hiker guru and I'm sure he can ID it!
KJ says this is anthelia (glove or waving hand coral). Common soft coral. Did you buy any? Could have come as a hitch hiker on another coral.