The octopus spies a nice, tasty mantis shrimp. It swims over for a closer look at the small creature. Then—WHAM!—the mantis shrimp strikes a nasty blow with its hammer-like forelimb. The octopus shrinks back, defeated. That wasn't such an easy meal after all . . .

In nature, good defenses can mean the difference between surviving a predator's attack and becoming its lunch. Some animals rely on sharp teeth and claws or camouflage. But that's only the beginning. Meet creatures with some of the strangest defenses known to science. How strange? Hagfish that can instantaneously produce oodles of gooey, slippery slime; frogs that poke their own toe bones through their skin to create claws; young birds that shoot streams of stinking poop; and more.