Web/cocoon building creature?

[Thespammailaccount]

Anyone might know what this is? It is in the macro tank. Looks like whatever it is has gathered larger pieces of sand and has wrapped them up in a web/cocoon?

 

[Thespammailaccount]

Bump

 

[Thespammailaccount]

@KJ

 

[duberii]

Could be tons of things- a lot of Polychaetes (idk if I spelled that right) build tubes made of sand. It could be a spinoid worm, which would have only 2 white tentacles that it extends to look for food. It could also be a bunch of other things from other polychaetes to tube-building amphipods. I'd say look for an opening hole and monitor it whenever you can.

 

[king aiptasia]

im surprised nobody mentioned sponges