Identify white stuff on LR

[clsimons29]

I have this white stringy like think growing on a piece of my lR and have no idea what it is. Any ideas?

 

[teen]

probably jsut some macro algae, maybe dead. its no harm. it wont bother anything and it might just dissapear. nothing to worry about.

 

[b-baby80]

sponge?

 

[clsimons29]

I don't think it is a sponge as I have other sponges growing in the tank and I do not think it is dead as it seems to be growing and nothing else was apparent there to cause die off. Thanks.