Koalas are known to be cute and cuddly, but they have a vicious cousin. Thankfully, this cousin, the Marsupial Lion, is now extinct. As it's name suggests, this animal was a marsupial so it carried it's young in a pouch, like Koalas and Kangaroos do.
It lived during the Pleistocene period - somewhere between 1.6 million and 46,000 years ago.