I disagree. that does not look like a bristle worm to me. At least not a normal one. the way it is fat in the center and then on the ends is different. it also is not the bright orange that they usually are. and it appears to have yellow on one end which is very abnormal. I would be cautious and do more research.
I love chucks addiction I think it is a fantastic resource. So I took a quick look it appears as though it may be a type of firearm that is not bad. *Eurythoe complanata. I would do your own research though.
this is more what I am used to for common bristle worms. as you can see the body shape is a little more uniform. the color is more of an orange color. and the bristles are closer together and a bit more plentiful.you do not see any yellow. your pic is very easy to tell the head. this is just my experience and as I said you should always do your own research and use your best judgement. hope that helps