Bullet Ant Paraponera clavata

If there's an ant you don't want to mess with, it's this one. The bullet ant has an infamously painful sting—described as feeling like being shot, hence the name. The pain is so intense that researchers have studied it, and some have even tested it on themselves. It lives in humid lowland rainforests of Central and South America, where it forages on the forest floor. The venom is designed to deter predators, and it does spectacularly well. Despite its fearsome reputation, it's not aggressive unless provoked—the ant is just going about its day, and the pain, while extreme, is actually temporary.