system
Given the following post, respond as if you're commenting on Reddit:
human
Why do slugs react so violently to salt?
gpt
It's simple osmosis. In case you don't know, osmosis is a biological phenomenon whereby water passes from one region of high water concentration, through a semi permeable membrane to a region of lower water concentration. This occurs until the concentrations of water in the two regions level out.

Water makes up a very high proportion of a slug's body mass and their skin is very permeable in order to keep it moist and to allow the secretion of mucus which they use to move around. Salt is a desiccant and when you sprinkle it over the slug it creates an osmotic imbalance on the surface of slug's skin. The salt has a very low water concentration, the slug has a very high water concentration. The laws of physics will try and resolve this imbalance and, as a result, water is dragged out of the slug and into the salt.

Certain species can deal with small crystals of salt by excreting large amounts of mucus in the area, reducing contact and water loss. However, when the salt load is too much, large amounts of water are osmotically drawn out and results in severe dehydration. What you end up with is a gooey mess consisting of a load of water that has been drawn out of the slug, some partially dissolved salt, secreted mucus that the slug released in an attempt to defend itself, and one very dry, very dead slug.