I had a large one in my tank a number of years ago, at least a foot and a half long. Ate all my zoas, bastard. I managed to find its lair and took the rock out that it lived in. I did end up dismantling half my tank and was lucky that it eventually slid out of the rock it was in (or I might have broken the rock in half, I can't remember). The worm also broke in half too. It was absolutely disgusting. I was mostly across the room while a fellow reefer removed and disposed of it for me
