Another ID question

[aquaantelope369]

What are these long black things inside the skeleton? Are these smaller bristle worms? You see them when I break them, then they disappear back inside.

 

[fishywishy]

Kind of looks like bristle star arms but it’s hard to tell.

 

[JoJosReef]

Hard to tell. Any way of grabbing one and getting it on a white background?

 

[aquaantelope369]

I wasn’t able to snag one. Very tiny and slippery. And as soon as I broke the piece, they retreated back inside. I could try to break another.