What is this?

[Mariette]

My pistol shrimp was doing a bit of remodeling and this showed up. No crushed coral of that shape in the tank for him to use. That’s him poking his head out for a photo op looks like a calcified worm?

 

[Gareth elliott]

Looks like a vermatid snail to me. Would remove or seal with super glue. Can irritate corals.

 

[Mariette]

Looks like a vermatid snail to me. Would remove or seal with super glue. Can irritate corals.

Thx