What are these white "pods" in all my crevices and caves?

[kinetic]

Just noticed a huge bloom of these weird white things in every crevice/cave that doesn't have light.

What is it? Should I be worried?

 

[Srt4eric]

Looks like pineapple sponges

 

[Kensington Reefer]

Natural filters

 

[Wlachnit]

Yeah...looks like a sponge.