This same worm, like centipede thing, was seen by me at a fish alive in durham, and he had about 10 hiding when he decided to clean the tank, he reckons that they were bad, but they looked so defensless, and he took em out and binned them. It only comes out every so often, and usually stays in the rock. I don`t relayy want to get rid of it if its doing nothing it should`nt be. Thought i found it in a corel, but remebered i found it in a piece of rock that i bought, with things sprouting from it, apparantly these things are bad for a setup also, these are like mushroom stems, with tenticles cuming from the body, and are kinda orangey/redy, colour.. i actually bought this as a live thing, and apparently its not good, so i`ve been told ive been ripped off.!!!