An evil koala, more commonly known as a "drop bear," is a fictitious Australian marsupial. They are said to be large, vicious and carnivorous animals that drop down from trees to attack their prey from above.
Despite being fictitious, the Australian Museum has extensive information on the animal. Known to them as the Thylarctos Plummetus, the animal is described on their website as being "a large arboreal predatory marsupial related to the koala." They also go on to describe the diet, habitat, size and identification of the animal. However, the distribution map they provide suggests the article is of a satirical nature.