Yet another 'What is this' thread ...

[Solga]

Ok everyone, I have a 'what is this' that I really can't seem to identify. I know it's not a fish (lol) and it's attached to the live rock, so I don't believe it's an invert. It was suggested that it could be a tunicate of some sort, but I can only see 1 hole on one end that opens and closes rather slowly, and I have read that tunicates have 2 openings.
This thing is shaped like a previous fat black sea cucumber that I had many years ago, but it does not move from the rock. It's about 3 - 4 inches long, about as big around (inflated) as a US 50 cent piece, inflates and deflates rather slow, and appears to be the same color as the live rock, only with wrinkly 'skin'. This thing is not hard like the rock, but does not seem soft or gooey either.
I have attached some pictures to try and help ID this thing...
I can take more pictures when the lights come on, if needed.

 

[vetteguy53081]

Appears to be a tunicate and would be a filter feeder

 

[Solga]

Appears to be a tunicate and would be a filter feeder

Thank you for the reply !! I do have a question for you though. Everything I have read states that tunicates/sea squirts have 2 openings or valves. Are there single opening tunicates ?

 

[Solga]

Just wanted to give an update and let everyone know, that I did find a second opening, or siphon for this. I guess what really threw me off, was that I could not find any other pictures of anything that looked like this, and the overall shape was not that of a typical tunicate.
Thanks again, for looking and replying !!!