Any idea what this may be?

[Matthias7]

This is a newly acquired coral. There is a hole about midway up the coral with something white inside that moves around. It's funny to look at it almost looks like the coral is "breathing". The coral also has a comensal crab on it I would assume is unrelated.

 

[saltyfilmfolks]

I don't know on the Id. But it's probaly a Coral barnacle.
Congrats on the crab btw. I love mine.

 

[Matthias7]

I'm fairly certain it's a barnacle as well. when I first saw I thought of the scene from the mummy when the guy opens his mouth and a swarm of insects fly out and devastate everything.

 

[Rick cowen]

I would agree on barnacle as well, gorgeous coral