Water bears are virtually indestructible

Tardigrades are tiny aquatic invertebrates, sometimes called water bears because of the loping way that they move. The largest species are 1.5 millimetres long, the smallest are under 0.1mm. Despite their squishy and vulnerable appearance, they are virtually indestructible. Experiments in laboratories have shown that they can survive pressures of 6,000 atmospheres, temperatures as low
as -272°C or as high as 151°C and radiation doses that would most certainly kill us a thousand times over.
They achieve this by dehydrating their own bodies using a special sugar called trehalose, which acts as scaffolding to protect the cell contents. Their water content drops to one per cent of normal in this state and their metabolism slows by 99.99 per cent. Ice can’t form in a body this dry and all the chemical reactions that might harm them simply happen too slowly to be dangerous.