White stringy things

[Sha]

As I’m moving everything into a larger tank I noticed these white stringy looking things. This would be where another rock was sitting on top of it. Anyone know what they are or how to get rid of them?
Thanks for the help

 

[*GAREEF*]

As I’m moving everything into a larger tank I noticed these white stringy looking things. This would be where another rock was sitting on top of it. Anyone know what they are or how to get rid of them?
Thanks for the help

Hard to tell from the picture but possibly some sort of sponge.

 

[Gumbies R Us]

@ISpeakForTheSeas

 

[56longroof]

My vote is sponge.

 

[Üter]

sponge