Any clue what this is?

[Kain]

it was a small rock , maybe 5 inches long and couple inches thick. I smashed it in 1/2 with a hammer and there is nothing left of those things on the remaining piece which is now a couple inches. If I see anything come back I will throw out entire rock. It

Anyways anyone know if my snails are toast?

The pump was shooting air bubbles into tank for about 10 hours and 3 out of about 9 snails fell upside down. I flippedthem back over, 1 is moving , another is moving only its antenia and another just goes in shell if i touch and does not move. Should I throw them out as well?