Looks like it could be pipe organ coral?? Not sure of the true name of it though. Or it could be some form of Acropora, many abnomal and deleterious conditions can result in polyp extenions, and beings you said it came in on LR it might be suffering or just having a hard time adjusting to your set up?? I'm just shooting in the dark here. It apears to be a hard coral but from a pic thats just a guess.