Help identify these creatures. Pineapple sponge?

[clown99]

I cleanout the media basket of my biocube 29 and found clumps of these things sticking to the sides of the media basket and walls of the chambers. They're the off-white tuffs in the GIF.
Are they pineapple sponge? What about the hard white specs? What are those?
Thanks in advance.

 

[James M]

Pineapple sponges...harmless filter feeders
White specks could be spirorbid worms but pic is unclear