Help identify please

[tmo65]

does anyone have any idea what these are? There’s hundreds of them whenever I change the filter sock. They don’t seem to move, but they look very much like worms. They have no bristles on them and they just would up in my 3 year old tank a month or so ago. Thank you

 

[KrisReef]

those look like tube worm houses. Lots of feather dusters make these houses to live in.