What is this strange luminescent spiral?

[ItsAName]

Saw this in the tank. It glows green like a coral in the tank. It's a spiral. When I took it out, it's brown and as thin as a sheet of paper. At first I thought my kid dropped something in the tank

 

[nautical_nathaniel]

It's the door from a snail, they sometimes shed or drop them. I find them in my tank from time to time.

 

[ItsAName]

Cool! Never noticed them being luminescent on the snail.