Empty tubes found

[Titans831]

What type of animal would live in these tubes? I’ve been finding them empty every so often in my tank. At first wasn’t sure what it was but recently I’ve caught a little arm or worm peeking out from under my live rock. Not 100% sure what it is but after talking to other reefers only thing I can think of is a bristle worm! Do bristle worms Live in tubes like this? Tried to catch it with tweezers but it retracts super quick! Any info or help would be greatly appreciated this is the evidence I have so far lol.. thank you!

 

[Auquanut]

I would say that the tube is from some sort of tube worm. Unfortunately deceased. Maybe a feather duster? As far as the "arm" reaching out, it could be a bristle worm, but sounds like a micro brittle star. We would really need a clearer picture to be certain.