Sponge or tunicate ID Pls?

[wloftin]

Can someone please help me identify this growing on the glass of the overflow of my tank? It appears to be a tunicate, but I'm having trouble getting a positive ID.

Thanks!!

 

[Bongo Shrimp]

Some sort of harmless hitchhiker sponge.

 

[mscarpena]

Sponge.

 

[wloftin]

The reason I thought it might be a tunicate is that it seems to have a gut and looks more complex than a sponge.