Strange looking blob under rock

[Jicklenop]

Not really sure what to call it, almost looks like a strange coral or sponge or something. They are under only one of my rocks, one that a goby, peppermint shrimp, and pistol shrimp like to hang. I've never noticed as I usually dont shine light under the rock but was looking out of curiosity today and saw them. Not on any other rock that I've seen

 

[Cthulukelele]

Pineapple sponge. Harmless filter feeder. Sign of tank aging somewhat stabilizing, so congrats!

 

[StartingATank]

Pineapple sponge

 

[rayadog]

^^