White goo?

[mh0ward]

Anybody happen to know what this white goo is? It seems like a clump of white goo in a small shadowy part of my rock, until it’s under microscope… then it looks more like white filament with some goo on it. Not sure if it’s good or bad.

 

[Tahoe61]

I am inclined to say sponge because of the location and fibrous appearance. Or dog hair. :)

 

[ISpeakForTheSeas]

Anybody happen to know what this white goo is? It seems like a clump of white goo in a small shadowy part of my rock, until it’s under microscope… then it looks more like white filament with some goo on it. Not sure if it’s good or bad.

That's a sponge, and your microscope pic there shows its spicules pretty clearly - neat, and it should be harmless/beneficial (bad sponges are rare).