What is this worm? Good or bad?

[reeefer]

Need help! Found this worm on a piece of lr when I pulled it out to glue a coral

 

[KJ]

Bristleworm good to heave.
They are great for overfeeding a tank. Best cuc.

 

[reeefer]

Ok thanks, I should have put him back in then!

 

[ahiggins]

I dont want them in my tank (Im sure I do though haha) they get big....and they can sting. Im constantly fiddling with my tank so not a good option for me lol

 

[LetItReef]

Your tank has probably have few of this and do they do multiply.