Fuzzy things growing in my sump

[Crown]

My sump has no lighting and no refugium.

Im running just a rollermat and live rock in my sump. But the live rock is growing sponge like things in the sump. It’s the brownish fuzzies on the purple live rock. Here’s a photo:

 

[fishguy242]

need a better pic, but guessing pineapple sponges ??

 

[Crown]

I added a few more photos. I thought pineapple sponges too, but don’t they usually grow on the glass? These are growing on the live rock

 

[reeferguy3303]

Those are pineapple sponges, they grow everywhere

 

[BelieveInBlue]

The pineapple sponges I have mostly grow on rocks, though some grow on pipes too. Usually the underside. I've never seen/heard of them growing on glass.

 

[fishguy242]

100% pineapple sponges

 

[Nemosis]

Definitely pineapple sponges. I have them as well. They’re filter feeders and pose no real threat other than being unsightly.