The crown conch (Melongena corona) is a common intertidal species along Florida coasts. According to Malacolog, the habitat of this species goes down to depth of only about a meter or so.
So, what does Melongena corona do when the tide is out? It buries itself in the wet sand until only the top of its shell is left exposed to the air. Here is one I photographed at low tide near Tampa, Florida last March.
To make sure it wasn't just an empty shell, I pulled it out of the sand and turned it over. The operculum and parts of the snail's foot are visible within the aperture.
Ilyanassa obsoleta, another intertidal snail along the eastern shores of North America, survives the low tide also by burying itself in the sand as illustrated in this post.
Two previous posts were about Melongena's siphon and the snail's behavior outside the sea.