pogonophoran worm

Anyone have any info on these little creatures. I googles it, but could not find the info I was looking for.
Basically, are they "reef safe" or will they cause problems? I believe I have several of them in my tank, but have no idea where they came from...probably hitchhikers on live rock.
This is also just a guess as I have no idea if that is what these things are. That is the closest thing I could find that by picture, that resembles/identifies them. I'll try to post a pic of the things in the tank...but was wanting some info if anybody has any.
 
Yes...the weblike, stringy, mucas, stuff...that is what I was worried about. It doesn't seem to be bothering anything, but is just plain ugly and a mess.
I just wanted to get some opinions ot info on them...
 
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