Help! Can someone ID this growth?

[stemonia]

I just noticed these small worm like structures growing on a couple of my rocks in my reef. They seem to be growing longer by the day and there are some growing on the back of one of my capricornus corals. Can someone tell me what this is? Is it dangerous to my tank and if so, how do I get rid of them?
Thanks!
P.S. I'm not sure how to insert images into my post so I also uploaded the image as an attachment to my post.

 

[stemonia]

Here are some better pictures of the worms

 

[sambasam]

looks like some type of tube worm. most of them are completely harmless and do a good job filtering

 

[stemonia]

Thanks! I sent the pics to my LFS as well. He told me that they looked like small tube worms as well and not to worry about them.

 

[mie]

I feel bad for you. my buddy just bought a tank that was set up and his live rock was COVERED with these worms his overflows were plugged from these things, they are hard and can poke you to the point to were they will draw blood (this happened to us) we had to kill all 200 pounds of his rock to make sure that they went away FOREVER these things multiply like crazy and your tank will become very unattractive and not function properly, there is no chemical to kill them or fish our lfs owner had them a few years ago and killed them with some type of acid. good luck