wierd worm thing at night?????

i have this weird thing that comes out of a hole in my rock at night. its black in color and stretches about an inch to two inches out of the hole and wiggles around and if i shine a light on it it goes back in the hole. its mouth opens up and it kinda looks like a small feather duster. i have no fricking idea what this is or if its bad. any ideas

 

usually red light is invisible to such creatures. I'd give that a try. You might re-arrange rockwork to get him. Try this guide to match him up to what you have if you cant get a picture:
Worm Hitch Hikers

 

Sounds like a peanut worm (completely safe) or a eunicid worm (not safe at all with soft corals)

 

For some reason this post reminds me of Monty Python's "Cake or Death?" skit.