Will a snail come out of its shell when it's dead?

In pieces yes, and the odor is most foul. If a snail remains unmoving for a couple of days and you still see a his shoe and wonder if he yet lives, simply pick it up out of the water and give it a sniff. It is unmistakable if it is dead. Snails grow their shells while crabs kill the snails for the shells or collect empty shells. As the snail grows so does it shell, where a crab must replace and upgrade its residence as it grows.