Flat-backed millipedes that defend themselves with cyanide have a fearsome foe in Promecognathus beetles, which are unfazed by the potent poison. A new study shows the beetles have evolved a unique tolerance for cyanide—rather than avoidance behavior or some other countermeasure—but the underlying mechanism remains unclear. (Photo by Josh Cassidy, KQED Deep Look, originally published in Weary and Will 2020, Annals of the Entomological Society of America)