 climb into plastic bottles and climb into plastic containers. And if the container is angled downwards, they can get out again. But if the container is angled upwards, they'll get stuck in the container and not be able to get out because their claws can't grip on the plastic and they can't get out the top of them. And what happens then is they die because it's very fast in the bottle and it kills them. But when hermit crabs die, they release a pheromone. The pheromone says to other hermit crabs, my shell is available, come and get my shell.