What is this?? *PICS*

[Canadbis]

First...I have tried taking pictures of it but the tentacles are so thin that they dont show up.
SOOOO a description of what I can see is the best I can do. I have seen 6-8 tenticles that seem to be able to reach about 14" in length, they are about as wide as a thread and feel all over with the tip. they are brownish in colour, and come out during the day. I have some spaghetti worms in another tank and they are not nearly as big as this thing I am describing. I assume it came in on the live rock, it hides behind/inside one of the rocks. I used a grabbing device to try and pull it out and it broke off the tenticle I was touching and pulled in. I have tried to no avail to see its body with a light. Doesn't seem to affect any coral that it touches and no livestock has dissapeared...yet.
Sorry but this is all I have at the moment.
IF I can get any type of pic that shows it I will post it up right away.