Please help identify this worm??

[Mioduz]

Im considereing the purchase of a 150 tank, its set up and the rock has alot of these worm things on it. Never seen em before my first thought was spagetti worms, but not a lot of knowledge of pests. What are these and are they bad?

 

[T-dub]

Looks like spaghetti worms to me. I wouldn't worry about them

 

[Bent]

In case your wondering what it looks like under there:

http://www.reefcentral.com/forums/showthread.php?t=2569222

 

[Sugar Magnolia]

Very beneficial!