There are few defences more extreme than that of the bombardier beetles. These insects deliberately engineer explosive chemical reactions inside their own bodies, so they can spray burning, caustic liquid from their backsides. The liquid can reach up to 22 miles per hour, at temperatures of around 100 degrees Celsius. It’s painful to humans—watch Ross Piper take one to the face—and potentially lethal to smaller predators like ants.

The beetle mixes its chemical weapons within glands in its abdomen, each of which consist of two chambers. The reservoir chamber contains a solution of hydrogen peroxide and hydroquinones—that’s the fuel, inert on its own but always on the cusp of extreme violence. The adjacent reaction chamber contains enzymes like peroxidise