Although a number of Eunicids are just scavengers, the problem is that it's very hard to tell which is which. If you haven't seen anything munched, it may be that yours is a scavenger, although I have also been told that some will change their diets over time. If you want to get it out without ripping the tank apart, try to locate the burrow. For worms of managable size, the method I've read to be most successful is to inject something like cream soda into the burrow to send it running out of the rock. Once the worm is out, wrinse the rock in clean water and let soak in a bucket for a while to make sure the soda is gone before it goes back in the tank. Of course, I haven't actually tried that method on my bobbit, so I don't know how easy it is to do successfully...but it's surely worth a shot before taking a hammer to the rock. Don't try to grab it with tongs or something though unless you see the entire worm exposed. If you are able to grab it when it's still hanging onto the rock, you'll risk breaking it apart when it tries to pull backwards. I've read conflicting info on whether the rear fragments will be able to recover, but it's probably not worth the chance.
and when i put light to it it just went back pretty fast a split second.
