The world's deadliest frog is harmless if you feed it the wrong bugs

A wild golden poison frog carries enough batrachotoxin to kill about ten adult humans, yet it makes none of that poison itself. It sequesters the toxins from specific ants, mites and beetles in its diet. Raise the same frog in captivity on fruit flies and crickets, and it grows up completely non-toxic.

— John W. Daly, H. Martin Garraffo, Thomas F. Spande, Consuelo Jaramillo, A. Stanley Rand, Dietary source for skin alkaloids of poison frogs (Dendrobatidae)? — Journal of Chemical Ecology, vol. 20, 1994