Odd white pest?

[MattLaw]

Hello all!
To be honest I don't know how to describe these things. They look a bit like tiny pineapples that are completely white. I have attached a picture to help. Now that I have spotted them, I see that there are tons of them. Does anyone know what these are? They are approximately anywhere from 1-3mm.

 

[chaples55]

They are indeed called pineapple sponges. Very common and harmless

 

[MattLaw]

Ohh okay, thanks. Lol, I felt a little silly saying they looked like pinapples, but I guess not!

 

[kodock]

2nd the above. Pineapple sponges. Great filter feeders. Completely harmless. I have thousands.