When you pour salt on a snail (or slug) the water is very rapidly pulled out of the cells of the snail's body by a process called osmosis. As it dries out, the snail's body produces a slimy substance to protect itself. The bubbling comes from the slime and air being forced out of the snail's body as it shrivels up.

What does it mean if a snail is bubbling?

While snails are known for being notoriously slow, slimy is their second name. ... Call them slow, but when a snail's survival instinct kicks in, snails are quite fast to produce a foamy, bubbly secretion to protect themselves from threatening situations.

What is the foam that comes out of snails?

Snail slime is a kind of mucus, an external bodily secretion, which is produced by snails, which are gastropod mollusks. Land snails and slugs both produce mucus, as does every other kind of gastropod, from marine, freshwater, and terrestrial habitats.