Snail is a reptile. There is some mucus everywhere it passes. It likes to live in the grass under the tree. If you find the enemy, just retract into the shell. Its hard shell can protect itself.
Snails think all the time, what if the sky falls and kills me? So it crawls with its shell on its back every day until it gets dark, and it sleeps comfortably in its shell.
Snails have no bones, so their bodies are soft, juicy and delicious, and they are often attacked by birds and other small animals. The snail shell is its "protective umbrella" and a refuge from danger. When it was invaded by the enemy.
Its head and feet retract into the shell, secreting mucus to seal the shell mouth; When the shell fails, it can secrete some substances to repair the body shell.