So, we have Cane Toads which are not native but introduced to battle the cane beetle…probably not someone’s smartest idea, considering the results; imported 100, introduced 3,000 back in the 1930’s and we now have millions and they are a pest!
Cane Toads are thought to consume approximately 200 food items per night, far more prey than most native frogs ingest in the same period. The bulk of the diet is usually ants, beetle and termites, although they can eat anything that fits in their mouth including a wide variety of insects, frogs, small reptiles, mammals and birds. In addition, Cane Toads have the potential to compete with native species for food and shelter sites. The ability of the Cane Toad to rapidly expand both its range and density and to consume relatively large numbers of a wide variety of prey has led to concern that the Cane Toad is a key factor in the decline in of many native species.
The cane toad in Australia is regarded as an exemplary case of a "feral species"—others being rabbits, foxes, cats and giant mimosa. Australia's relative isolation prior to European colonisation and the industrial revolution—both of which dramatically increased traffic and importation of novel species—allowed development of a complex, interdepending system of ecology, but one which provided no natural predators for many of the species subsequently introduced. The recent, sudden inundation of foreign species has led to severe breakdowns in Australian ecology, after overwhelming proliferation of a number of introduced species for which the continent has no efficient natural predator or parasite, and which displace native species—in some cases these species are physically destructive to habitat as well. Cane toads have been very successful as an invasive species, having become established in more than 15 countries
We, well me at least, do not actually go around licking Cane Toads but they have been known to kill a few dogs and cats.
http://io9.gizmodo.com/how-toad-licking-gets-you-high-and-then-kills-you-1642946043