Epiphragm

An epiphragm (from the Ancient Greek ἐπί, epi " upon, on, over " and φράγμα, -phrágma "fence") is a temporary structure which can be created by many species of shelled, air-breathing land snails, terrestrial pulmonate gastropod mollusks.

In most species, the epiphragm is made of dried mucus, and although it is elastic, it is fairly easily torn when forcibly removing a snail from its substrate.

Most land snails are only active when the humidity is high such as after rain and at night, and become inactive during dry weather.

[2] In most species of air-breathing land snail, the epiphragm is a simple membrane composed of layers of dried mucus.

Helix pomatia snails hibernate for many months buried in the soil, and a strong solid epiphragm protects them not only from desiccation, but also against attacks by soil-dwelling predators such as carnivorous beetle larvae.