What Is That???

[sduerk]

after rearranging the rocks in my reef I found what looked like a worm attached to one of the rocks with "mucas" coming from it's mouth. I figured it was dead but the tube was more like a hard shell and there was indeed some sort of creature inside. now, surrounding his "tube" is something like a mucas "web" all over the rocks. What is this thing and what should I do about it?

 

[sduerk]

Well the tube is about 1 1/2 inches in length and sort of curved back around on itself. the creature that sticks itself barely out of the hard tube/shell looks like it has two antenna like on a snail. When I stoop to look at it it ducks it's head back in. The tube is white with sections throughout it where it has grown and is around 1/4 of an inch in diameter. Best I can do.