Can someone please help me I.D

[jrid1997]

I dont know what these things are there are like 35 of them in my tank most are on the back glass I can only find one on the rocks. They aren't very big but you can easily see them because of the black background. I started with dry rock and sand and only have two clownfish and a yellow tang never let LFS water into my tank either. Sorry for bad pics they are hard to get

 

[jrid1997]

Never see them move either

 

[pugcrush]

pineapple sponges; good guys - means your tank is maturing