Hitch hiker ID

[AndyL]

See that's exactly what makes me think it's not a vermetid snail...

That whole 'yellow' area moves opening a gap for the tentacles / mouth to be revealed at the top (definitely not mucus - they are tentacles much like an anemone's) in the second shot you can see the actual web it produces (that white line coming out).

Its definitely not coiled, when it opens up to eat the spider web, the whole top opens, exposing about 6 tentacles, and the black/white striped mouth. More like what one would expect from a clam than a tube worm.

FWIW I've also got some of the vermetid worms on some other LR in the tank - they are as advertised, redish tube worm like base, puts out a similar spiderweb - but nowhere near as big (covers 1-2 sq inches, the one in question can almost cover the whole footprint of the 2.5 - 6x12).

Andy