Worm ID help! Ty

[40B Knasty]

Not sure what this is. Sorry about the picture not being clearer. Not my tank or picture.

 

[DSC reef]

Resembles a dorvellidae worm

 

[40B Knasty]

Resembles a dorvellidae worm

Are they harmless? The person has an octospawn, Zoas, clown fish, fire fish, and prawn goby.
I did a little research. Seems like they are sub species to the bristle worm that eats like a bristle, but just an uncommon worm to get in a tank

 

[DSC reef]

They are scavengers and pretty much disappear on there own depending on food source but I wouldn't have a worry about the corals.