Water bears, as creepy looking as they are, had been a favorite among scientist to study. They are known to survive just about everything, from X-rays to high exposure to hydrogen peroxide. The protein that is responsible for the water bears' strong resilience is Dsup, a damage suppressor. The protein helps by wrapping around nucleosomes, protecting them from DNA-damaging chemicals.
Sometimes it is amazing to see how small critters, like water bears, can be so resilient to the environment. Hard to imagine they can survive harsh condition when they are so small! I think it pretty amazing they have evolved in way to fight against the odds of their survival.