The big thing is a feather duster as mentioned above. I see three other things in that red circle: some red thing on the far left that’s too blurry for me to distinguish what it is, a tube with algae growing on it just to the right of the red thing (I’m not sure if it’s a large spirorbid worm tube, a smaller feather duster tube, or possibly something else like a vermetid snail tube - if you see anything come out of it, like the crown of a feather duster worm, a pic or description of it may be helpful for ID), and something indistinguishable on the far right just under the feather duster’s crown.