This black-spined toad's "venom" is a toxic skin secretion that tastes bad to potential predators. It's released from the parotoid glands, those large bumps behind the toad's ears. Toads release the substance when they're seized, and even a small amount of it can sting human eyes. So wash your hands after picking up toads, and don't worry about wartsthat's a myth.
Photograph copyright Tim Davis/CORBIS