ID?

[RN7]

What seems like clusters of tube/rod shaped eggs, open on one end, appeared quickly on open sand and a small spot on the base of a rock in shade within a couple square feet.. I thought nudibranchs but the mass is more of a wirey "neuron network" inside the cluster and could be a bunch of bugs locked together. They don't move as far as I can tell and I can take a skewer through the mass and grab a goo ball.

I don't see any on corals and the tank is 8months old.

"Close up" is pulling apart the sand on a cap.
"close up2" to is what it looks like on the sand bed.

 

[Billdogg]

Looks like a sponge of some sort to me.

 

[RN7]

I've gone to a few shops and seems to be the consensus... Thank you.

Also thought I found rolled up yellow worms in a pocket under a rhodactis and was told it was the intestines after trying to remove them...