Snail without a shell?

[Andy Reed]

My LFS gave me a couple of shells they thought were empty for my hermit crabs to grow into. When I opened the container I found this. Any idea what it is? It kind of looks like a snail that's lost its shell.

 

[SeaworthyAquatics]

Stomatella. Awesome CUC.

 

[Cnidoblast]

He's cute

 

[Andy Reed]

Awesome, thank you. He's in the tank