what could it be?

[bigmoe21]

hello
i just saw that there was a slender black arm, kind of banded arm, coming out of one of my rocks. it was moving about and seemed to be looking for something then something came out of the end of its arm similar to a feather duster. I know its not just one arm because when i picked up the rock i saw two more arms retracting back into the rock.
any ideas what it might be??
thanks
ill try to get a pic

[bigmoe21]

http://i217.photobucket.com/albums/cc47/bigmoe21/1203071716.jpg

[bigmoe21]

http://i217.photobucket.com/albums/cc47/bigmoe21/1203071718.jpg

[bigmoe21]

maybe its a peanut worm? not sure but what i was reading they showed a peanut worm that fit the description of what i saw except the one i saw is black..if it is i think i unserstood that they were harmless..anybody? thank you

[copperband]

peanut worms are good they eat detritus

[envy]

i thought peanut worm colors are usually shades of gray or brown, with occasional reddish, purple, or green pigment in the papillae and/or tentacles. diddn't know they were black. might be something else

[blueboy]

looks just like some in my tank, been there for years. i think they're peanut worms.

[caferacermike]

Peanut Worm.

[ST3PH3N]

def peanut worm