Not normally considered a protective substance, especially in nature, glass is usually associated with cracking easily. Except that in this case it’s being used by the toughest of all creatures to keep itself alive. Yes, the tardigrade. The way a tardigrade survives dehydration indefinitely is by wrapping its internal proteins in a glass like structure that hardens during desiccation and protects the rest of its body. It’s a bizarre defense against dryness, but clearly, it works.