Need help IDing

[KrisGeorge]

I'm relatively new to the reefing world. I did a TON of research before starting & while my tank was cycling. Tank is now 6 months old.
For the most part it's gone well, but then I noticed these in the sponge filter. Can anyone help me ID what this is? And is it good or bad?
Thanks

 

[KJ]

Sponge harmless.

 

[Biglew11]

Yep pineapple sponge good filter feeder. Harmless.

 

[KrisGeorge]

Thank you. I had heard of them, but wasn't really sure what they looked like.
I've read it's also a sign of a healthy tank. I hope that's true.

 

[4tanks]

Yes good sign healthy tank