When a puddle dries, some tiny water bears can curl into a waiting form.
Tardigrades are microscopic animals, and some species tolerate losing most of their body water. They contract into a compact state often called a tun, in which activity slows dramatically. This is a pause, not invulnerability: the ability depends on species and conditions, and survival is not guaranteed in every extreme.
A study of Hypsibius dujardini found that drying switches on genes for tardigrade-specific proteins. When researchers disrupted several of those genes, the animals became much less able to withstand desiccation. In laboratory tests, the proteins could form a glass-like state as water left, helping protect sensitive cell components. The finding reveals one part of a larger survival toolkit, not a single magic shield.