Any idea what these are, guessing a sponge?

[EstelleOrain]

I noticed these a few weeks ago but they have almost tripled in size since then, anyone have any idea what they actually are? I'm guessing some sort of sponge but they are so weird looking.

 

[inferior plank]

They look like stolons from those clove polyps(Clavularia) nearby.

 

[EstelleOrain]

Ah, I thought they might be the clove polyps when I first saw them, but since they were not connected to the main group figured they might be something else. Thanks for the ID!