What is this thing on my new live rock?

[rab6326]

I just put a few pieces of live rock in to seed my base rock and this is by far the most interesting thing yet. Anyone know what it is? It seems to swell up then shrink every once in a while.

 

[James623]

Looks like a tunicate.

 

[rab6326]

That's what I think too. It opened up a little while after my post.

I'm not too confident on it surviving since the tank just started cycling a few days ago.

 

[James623]

There could be a chance