Sponge? Or something else?

[SuncrestReef]

I have several of these small brownish growths in shaded areas of my rocks, each about 1/4" diameter. Could these be some sort of sponge?

I took these photos after lights out using a flashlight and my macro lens:

 

[Gonebad395]

Doesn’t look like no sponge #reefsquad

 

[SuncrestReef]

After a bit of research, I'm starting to thing these may be some form of tunicates.

 

[KJ]

Colonial tunicate.