White substance?

[Water4all]

Hello everyone,
This tank has been going since 2002 and I keep it mostly natural aside from once a month water changes and feeding. I give it calcium every so often for the stonese.

A week ago I noticed this white substance that seems to be around the rocks. It looks almost like bubble gum in the gaps of the rocks and someone has tried to pull the rocks apart with it on there. It has not damaged anything and seems to be kinda just there.

I see holes in it like you would if you saw a funnel spider here on land. Can anyone give some insight? Is this natural from a critter or something else?

50 gal
Salinity is 1.25
Running reefbeats lights
I havnt run test yet, but everything inside my tank is happy and normal!

2 clown fish
Devil Damsel
Duncan
Zoas
Long tent anemone
2 rock flower anems
Favia
Gap
Common inverts and the snail that likes to go in the substrate.
Thank you all in advance!

 

[dwest]

It’s hard to tell but I’m guessing a sponge.

 

[Water4all]

Better pic. I noticed in this one there looks like little sacs.

 

[Water4all]

It’s hard to tell but I’m guessing a sponge.

Thank you! I just put up a better photo after seeing those load up lol

 

[Water4all]

Better pic. I noticed in this one there looks like little sacs.

Okay after you said that I was able to find a thread on here and I'm pretty sure that's what it is. Cool and random I guess. The holes must be the worms going in and out of it. Thank you!