seriously weird. Is it pretty mobile? the base looks like cucumber/snail/nudi, but the top is strange. Would you say it is radially symetrical or does it seem to have head/mouth and tail ends?
wow, i just googled fuzzy snail and got this: http://www.reef-geeks.com/forums/befuddled-geeks/1102-new-tank-new-fuzzy-snail.html
Is it possibly a snail with hydroids/polyps growing on it? pic 3 of yours makes me think no, but the tube mouth looks like snail (and probably reef safe if it is filter feeding)