http://www.sciencemag.org/news/2019/10/one-these-deadly-viper-other-harmless-toad-can-you-tell-difference

The Congolese giant toad, which grows to the size of a small hand, would be a hearty meal for any predator. But it escapes being eaten by birds, lizards, and snakes with a trick never seen anywhere else in the world: It looks and acts just like the Gaboon viper, one of the most venomous snakes in Central Africa.

Many animals imitate dangerous ones to avoid being eaten. Viceroy butterflies are colored like the toxic monarch, for example, and many harmless snakes mimic venomous ones. But this is the first time a toad has been found to mimic a snake.