ID help

[Jeremy_d]

This thing is tube shaped and I just noticed it today. I regularly look at this part of the tank as it is where my pistol shrimp and goby routinely have their cave entrance. I have sand and rubble harvested direct from the ocean in this tank. Tank is mature and well established.

 

[ISpeakForTheSeas]

Looks like either a peanut worm (Sipunculan) or spoon worm (Echiuran). I'm leaning toward peanut worm, but either way they're most likely harmless/beneficial.

 

[Jeremy_d]

Here is another, better, image. I tried to siphon it out and ended up picking it up with my fingers. It is hard like shell/rock and seems broken on the end

 

[sfin52]

Here is another, better, image. I tried to siphon it out and ended up picking it up with my fingers. It is hard like shell/rock and seems broken on the end

Could be a type of coral since you harvested rock directly from the ocean.

 

[ISpeakForTheSeas]

It is hard like shell/rock and seems broken on the end

Well that changes things. Pencil urchin spine maybe? I know Eucidaris thouarsii can have spines that look like this sometimes.