Beetles, the Bombardier breed...
I heard about this bombardier beetle and had to learn more. Check this thing out. So wicked! It has evolved a self-defense mechanism that actually contains chemicals which are used in rocket fuel. Rocket fuel beetles. Actually, there are several types of bombardier beetles all over the world and each has their own gnarly defense mechanisms. Whoever thought beetles were harmless was wrong. So wrong! Check these suckers out: www.wired.com/2014/05/absurd-creature-of-the-week-bombardier-beetle/