Worm, star, or something else?
 

I saw this thing crawling out of my rock during day and night. At first I thought it was some kind of worm but then I saw 1 or 2 more "threads" right next to it. It looked like it was trying to catch some food that is going through water. It looks like bristleworm but it's not red and black and it's very thin. It is segmented into black and white lines and it has lots of small "legs" like bristleworm. But as I said it might be feet from some kind of star because there were 2 or 3 of them right next to each other.

Thanks for the help.