Australian Common Crow Euploea corinna

Meet the 'crows' of the butterfly world—a dark, blackish genus of milkweed butterflies that earned their common name through sheer coloration. But here's the secret weapon: they're poisonous, accumulating toxins from their milkweed diet as caterpillars and retaining them as adults. The caterpillars advertise their toxicity with bright colors, warning predators away before they even taste one. Unrelated butterflies have even evolved to mimic their appearance, getting poison-free protection just by looking the part—predator psychology at its finest.