White thing on GSP

[hey.al]

This white sponge like thing appeared within a day on my GSP. I found a similar thread that had mentioned it may be a harmless sponge of some sort but it wasn’t actually identified. Does any one know what it might be? Even if it is harmless, I am not really into the look and would like to remove it. Any tips?

 

[brmreefer]

Harmless Sponge.

Removal? Personally never bothered with it.