Please identify

[kmullen1]

These critters are growing in a little “cave” in my rock. My clownfish is very curious about them, she often hovers in front of them for several seconds. They seem to be growing pretty quickly. They are white, kind of shimmery when I shine a light on them, have tentacles that circle the tops, +\- a 1/4 inch. Any ideas??

Thanks!

 

[RedoubtReef]

pineapple sponge. Harmless.

 

[kmullen1]

pineapple sponge. Harmless.

Thanks!! Glad I didn’t pluck them out. Off to research them!