Australia just turned loose a tiny predator the size of your fingernail, and within minutes, scientists watching the experiment unfold could not believe what they were seeing. The most destructive invader in this continent's history, a poisonous monster that has killed crocodiles, dingoes, and entire populations of native wildlife for almost a century, is being torn apart in the dirt by a creature so small most people would step on it without noticing. Every chemical, every trap, every government program had failed for ninety years. And the answer the researchers just stumbled onto was hiding under their boots the entire time.