Possible feather dusters not sure and white tubes

[Galvan]

in cleaning my glass the other day I noticed a red spot in the rock and when I came close to it the creature disappeared. I waited a few seconds it popped back out and I passed the cleaning tool by it and again he retracted. It certainly does look like a very small feather duster. Now in the 2nd pic I have noticed many small white tubes under my rock and in same cases on top of the rock. What are all these white tubes? And is that one really a feather duster.
I'm sorry about the pics I'm not sure how to get them into scale. appreciate your thoughts.

 

[Len]

I think they are be Serpulid worms (small feather dusters with hard shells ... they will not grow big). It's also possible some are Vermetid gastropods - not worms at all, but more related to snails and clams. They also form hard white shells and extend feeding apparatus that resemble feather dusters.

 

[rbursek]

I have a rock with about 10 on them. my mentor has a ton of them in his fuge/ref they never get any bigger, but are good
Bob