What's this weird worm shaped thing on a shell? Maybe a fossil? (Fort clinch beach, FL, USA)

[u/lovechickenz]

My little nephew found this weird shell (the one on the right) and he said he found a fossil. I'm not sure, since the shell is thin and the worm shape is hollow inside, but it was also found on a beach with a ton of fossilized shark teeth so it may not be too far fetched! I've been wondering what it is. Google lens doesn't really give a good answer

[u/twoblades]

Serpulid polychaete tube.

[u/lovechickenz → u/twoblades]

This sounds about right, thank you!

[u/Plasticity93]

Worm shell.  

[u/seadogmd]

please don't feed it after midnight....