What are these white pods growing in every cave/crevice?

[kinetic]

Are these some kind of sponge? Just noticed a huge population of these little white things growing everywhere where there isn't light.

Should I be concerned?

My tank is about 4.5 years old. Earlier this year I added "Reef Rubble" from AquaBiomics (https://aquabiomics.com/product/live-reef-rubble), and recently I've seen a huge increase in little white pods everywhere. Is this something to do with all fo that?

 

[fishface NJ]

looks like pineapple sponges

 

[homer1475]

Pineapple sponges. Harmless filter feeders.

 

[kinetic]

Wow thank you for the incredibly fast responses. I couldn't "search" anywhere, because there was no way to describe it. Now that I have a name, I can find that everywhere. Thank you!

 

[KJ]

Sponge harmless.