Answer: Millipedes

The world is filled with deadly (but tiny!) creatures that should really make us appreciate how small they are, how big we are, and how we’ll never be chased down an alley by them.

Among those creatures are millipedes. While many millipede species have defenses as benign as curling up into a tightly armored ball to avoid predators, many of them have more deadly defenses. Members of the Glomerida and Helminthomorpha orders of millipedes, for example, have developed a wide variety of chemical weapons to use against predators including the secretion of caustic and poisonous compounds.

The most potent chemical weapon, however, isn’t found in the two aforementioned orders, but in the Polydesmida order, whose numerous species are able to produce hydrogen cyanide in doses high enough to kill birds and small mammals. Even more fascinating, the millipedes have evolved a very strong resistance to cyanide, making them immune to their own weapon—they can release the hydrogen cyanide in an enclosed space, kill the creature preying on them, and scurry away unharmed.