Yellow/orange stuff on rock

[amigo003]

does anyone know what this yellow and orange ish stuff growing on my rock is? Looks cool, but I have no clue what it is.

It’s been growing very slowly.

 

[bluemon]

Sponge.harmless

 

[amigo003]

Sponge.harmless

Cool, so just let them grow. Thanks for the quick response

 

[bluemon]

Cool, so just let them grow. Thanks for the quick response

Yea, I’ve had the exact same kind on a rock for almost ten years now. Didn’t grow much, but didn’t die