The bombardier beetle, Brachynus explodans has evolved a really cool defense strategy for dealing with aggressors, namely it sets off a small explosion of corrosive gas in their faces!

Inside a small bladder, hydrogen peroxide is catalytically decomposed to water and oxygen, with the enzyme catalase. This is mixed with the chemical hydroquinone (23% peroxide, 10% hydroquinone) and held two storage bladders until needed. Remarkably this highly reactive mixture can be stored for extended periods of time, due to the beetle adding another chemical which inhibits the oxidation process. The beetle has two tubes on its tail, and when faced with danger, swings around and points these combustion tubes at its enemy. The stored mixture of hydroquinone and peroxide is forced out of the bladders and into the combustion tubes, where it reacts with two enyzmes, catalase and peroxidase; also produced by the beetle.

Catalase breaks down the peroxide into oxygen and water, and the peroxidase turns hyroquinone into a range of irritating chemicals, quinonesnoxious. This happens so rapidly the mixture heats to about 212C, and due to the reaction releasing oxygen, suffiecent pressure is generated to blast the whole hot corrosive, irritant mixture over any aggressor.