Sponge? Barnacle? What is this?!

[Oddomatic]

This thing is pretty creepy looking, and It's growing on one of the sides of my rock cliffs... Anyone have an idea of what this thing is, or what it's diet might be? In thinking a sponge or maybe a type of barnacle, but I'm not sure. It doesn't seem to be a traditional barnacle because no feather dusters come out of this opening. It's mouth does open very wide though at times, and clamp shut at others. It almost looks hollow when its open. As a side note the reddish brown exterior is soft and malleable. It flexes and moves often when the inverts crawl over it...weird.

 

[Jc lover]

Looks like a barnacle for sure

 

[Coral Theory]

This looks like a tunicate.

 

[Oddomatic]

Hmmm, I guess it does kind of resemble a Tunicate. Could be...

 

[Oddomatic]

If he is a small Tunicate, I hope he can survive off of bacteria/detritus in the water column. I really don't plan on dosing phytoplankton just for him. I don't have many filter feeders other than a few random feather dusters here and there.

 

[jaBX1]

thats just a butthole, the rock's butthole...