D3O

D3o is a special kind of material that is squishy when you touch it slowly, but gets hard quickly when you hit it hard. It's kind of like magic because it can protect things from getting damaged. Imagine wearing a helmet made of d3o - if you were walking slowly, the helmet would be soft and squishy like a regular helmet. But if you fell down or someone hit you really hard in the head, the d3o would become hard and protect your head from getting hurt. That's why some people wear clothes or gear made with d3o to keep themselves safe when doing activities that might be a little dangerous.