Problems in paradise

[marie]

or "Can anyone tell what the heck is chowing down on my coral?"
Unfortunately I can't give you a pic of the creature or even a discription but it builds a tube that isn't hard and has some sand incorparated in the tube.
It doesn't appear to actually live in the part of the tube that I can see because I've tried to kill it and it keeps coming back

This is the damage done last night. It is removing all the tissue from my millie leaving the skeleton behind. The arrow is pointing to the end of the most recent tube its made

Any ideas on what it is? and more importantly how to kill it??