ID please-formations on rock

[Blakjax]

Any idea what these mounds are? They each have a hole and they seem to be forming in many regions of my rockscape.

 

[Cell]

I'd say they are some cool looking sponges, but not positive.

 

[ying yang]

Barnacles maybe?
Just guessing

Look 5 and 6th image,looks like them.but i not actually sure.could be sponge like cell said

 

[brmreefer]

Are they soft like sponges?

 

[Dan_P]

Any idea what these mounds are? They each have a hole and they seem to be forming in many regions of my rockscape.

Looks like a sponge. It will probably need to be fed.

 

[vetteguy53081]

Tunicates and not uncommon