The bombardier beetle defends itself by spraying a boiling-hot chemical jet.

When threatened, a bombardier beetle mixes chemicals stored in separate internal reservoirs, triggering a reaction that heats the resulting spray to near the boiling point of water. The beetle expels it in rapid, audible pulses aimed precisely at attackers, thanks to a flexible, rotating nozzle at the tip of its abdomen.

The reaction happens fast enough, and is controlled precisely enough, that the beetle doesn’t harm itself in the process, even though the chemicals involved — hydroquinones and hydrogen peroxide — are dangerous in their own right. The mechanism has long fascinated biologists and engineers alike as an example of finely tuned biological chemistry.