Live Rock Growth in no light area

[2Shainz]

Just was shining a flashlight in the tank and noticed these white or grayish looking growths on the bottom and backside of some live rock. Completely shaded from light.
Anyone deal with these before? What are they?

 

[kashman100]

Types of sponges. Totally normal and good for the tank

 

[2Shainz]

Types of sponges. Totally normal and good for the tank

That's what I was thinking and hoping. Thanks for the help.