what the...ID please

[daitheflu20]

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</u>Anyone know what this is? Some sort of worm that has used sand to build a tube and now has 2 'somethings' sticking out digging around the tank. I've highlighted the 'somethings' in the red on the second picture.

 

[george]

Harmeless scavenger and a healthy addition to the tank.

I forget what they're called, though. Medusa Worm maybe? They're in Anthony Calfo and Bob Fenner's Marine Invertebrates book, but I don't have it with me.