Here’s how tardigrades go into suspended animation
Chemical changes to the amino acid cysteine trigger what’s called the “tun” state

Tardigrades, like this one stained with a dye to show its internal organs, can survive extreme conditions while dormant. Scientists have discovered the chemical signal that causes the animals to hunker down and wake up again.
A.L. Smythers et al/ PLOS ONE 2024 (CC-BY 4.0)