Tiny White Worm with Bristles?

[jellifishi]

Please see the images I attached. I was looking at my copepods among the sand and saw these super tiny white worms that are sticking to the glass. I couldn't find a match online. I put one under a microscope and this is what I saw, initially I thought bristle but it didn't match.

What are they? Good or bad?

 

[ISpeakForTheSeas]

Please see the images I attached. I was looking at my copepods among the sand and saw these super tiny white worms that are sticking to the glass. I couldn't find a match online. I put one under a microscope and this is what I saw, initially I thought bristle but it didn't match.

What are they? Good or bad?

Those are definitely technically bristleworms, as the term bristleworm technically applies to any worm from the taxonomic class Polychaeta (segmented worms with multiple bristles) - in the case, I'm not sure what specific kind of bristleworm this would be though.

The shape resembles a Dinophilid worm, but the starkly visible parapodia (the "feet" where the bristles leave the worm) eliminate that option. At the moment, I'm inclined to think this critter is in it's larval stage, and that it's body will change (hopefully to something more recognizable) as it grows.