Need help identifying these growths

[JChurch]

These tube like structures have been growing in my tank for the past several months. Sometimes they will break off but grow back. I’m not sure what they are and if they are good or bad for my 29 gal biocube. Any help is greatly appreciated. Thanks.

 

[ndrwater]

Looks like sponge, which is a good thing

 

[JChurch]

Looks like sponge, which is a good thing

Thanks ndrwater!