Mystery string.

[sleeper]

I have noticed this thing coming up out of my sand everyday after the lights have been on before.

It's the very thin yellow string looking thing in the middle of the picture.

Some kind of filter feeder? Do I want it? If not, how do I get rid of it? Gravel vacuum, is what I'm thinking.

 

[saltyfilmfolks]

Does it retract if you touch it ?
Does the thread have any shape? Like feelers?
Likely harmless.

 

[Palyzoa]

Might be a tube worm, or a vermetid snail. Check here https://www.lionfishlair.com/hitchhikers-guide/ and see if anything fits.