Help. What are these?

[Brettdis]

Found a bunch of these fuzzy white things in my tank today. They seem to be on all the rocks. Anyone know what they are? I’m new and having a hard time posting a pic so bear with me. Thanks in advance

 

[bribo12]

Pineapple sponge. Harmless filter feeder

 

[Brettdis]

Thanks. I will do a little googling about them.