[muck]

Found on another board:

I found the culprit of the Astrea snail deaths in my Reef tank. I had
(emphasis on past tense) a large worm (18 inches long, 1/4 inch in
diameter) that I caught devouring one of my snails last night. This
beast was hunter orange with a hint or red, and had a row of feet down
both of its sides. It was lightning fast, so I had to remove the
rock that it was burrowed into, from the tank. The only way I could
get rid of it was to drop Kalkwasser with an eyedropper into the
burrow where it was hiding, and then it slithered right out (freaked
my wife out, who was helping me <grin> - she's a good sport).

Anyway, if you have such a beast, beware.