Huh. Well, I'd say it wants more light (raise it slowly so it doesn't pout). And that worm...it wouldn't happen to look like a white millipede by any chance, would it? If so, there's a decent chance it's being an idiot and is pinching at the polyps and trying to steal food from their mouths. I had a real problem with those "millipedes" harassing the heck out of the sickly dendros who came with my tank. The little buggers lived inside the coral's exposed skeleton and would come out whenever I fed it to steal food right from them! I dealt with them so the dendro's fine now.
Also, are there any asterina starfish in the tank? Our one zoa colony has a problem with them. Every few months, the asterina start attacking the colony for some reason, crawling onto their stems and gnawing on them. They end up taking little chunks out of their stalks, resulting in a bunch of polyps falling off. No clue why it happens, but the assault lasts for a few weeks (we have to knock the starfish off several times a day), then suddenly stops and the zoas recover.