I found this about a week ago, living in a piece of rock. I can't work out if it's a worm or a tentacle, though the way it waves about I'm leaning towards tentacle - it moves a bit like an elephant's trunk. In these pictures about an inch is sticking out of the rock, though I've seen twice that. Also, there are at least two of them, looking like two tentacles attached to the same critter. There has never been any live rock in the tank, so it must have come in with a frag (the last addition being well over a year ago).
Any ideas?
Any ideas?
