Over the past week I have seen this creature that, in describing it to you, will either make you laugh or cringe. I can not get a decent picture of it, because it lives in a very dark spot in my tank in a crack between two liverocks.
The part of it that I can see is the length of your pinky finger, and it is the same thickness and shape as a medium sized screwdriver shaft. I see no eyes or facial features. The creature in question exhibits a proboscis-like motion, protruding down from inside a rock and reaching about like an elephant's trunk. It touches the live rock, sits there for a few moments as if contemplating it (Tasting it perhaps? Depositing waste?) and then recedes back into its hole (Which I know HAS to be there, but I can not actually see it).
It is tan in color, but where a worm would have its thick band this creature has a black one. It seems to telescope into itself, much like a worm would do if you touched it.
The closest thing online I can find is a Lugworm. And I can only base comparison off of the non-bristled and thin part of the images I have found. It is NOT a snail, or a bristle worm.
Anyone care to venture a guess? Below is my guess as to the culprit. Colors are different, but the shape is so close it is hard not to consider it. But these live in sand? This thing is living mid tier in my water column in the rock??