I have had a 10gal tank for a few months with about 6 lbs or so of LR. I have a clownfish and an anenome and a small amount yellow pollyps and small amts of other assorted reef stuff. I was feeding today and noticed my largest rock (2lbs) had a long pink spiked wormy looking thing come out of it that i have never seen before. i only saw one side of it and it was about 3in long , but has to be at least 6in total, since it was still getting fatter as it got closer to the hole where it burried. then out of almost every hole in the rock, more of these things started crawling out, must have been 10 or so all smaller than the first they all poked around and went back in about a minute later. i have never seen these before, why did they all come out all at once? i'm assuming they are bristleworms, is this correct?