small white worm?

[Carlson Moncrief]

Anybody know what this may be? You can tell its size compared to the pinapple sponges its next to in my sump

 

[scottsdale454ss]

Pretty hard to tell from the picture

 

[Carlson Moncrief]

I looked with a magnifying glass and it appears to be a very small feather duster in my protein skimmer chamber. Do you think its different from ones bought in stores? Or could it eventually get that big?