What: The thylacine, a predator known to Australia and its surroundings, until its likely extinction in 1936. This one, the last known in captivity, was named Benjamin:

Why: The thylacine may have been the world’s least understood animal in its day. Popularly called the Tasmanian tiger (except it wasn’t a feline) or the Tasmanian wolf (except it wasn’t a canine), the thylacine was a marsupial of the order Dasyuromorphia, where the rare carnivorous marsupials like the Tasmanian devil and banded anteater hang out. It’s proof that the dog and bear exist because they must. In Australia, normal predatory mammals never developed, so marsupials had to make do. And boy, did they. Take a kangaroo, stretch it out, give it jaws that open 120 degrees, band it up with stripes, and you’ve got the terror of the Australian plains. But it’s also uniquely marsupial: it couldn’t really run at high speed, but instead hopped briskly like a kangaroo. It’s also the only marsupial where both genders had a pouch, the oddest evolutionary development this side of the platypus. The thylacine was king of the misfit beasts.

Impact: The thylacine ruled Australia and Tasmania for 20 million years. Then, like all apex predators, the thylacine took a back seat to the apexiest of all predators: us. At some point, the dingo was brought to the Antipodes, and those dogs get a lot of the blame for driving out the thylacine. But I don’t buy it. The two species hunted in different parts of the day, and would rarely have fought. It is much more likely that the dogs that hunted thylacines were on the ends of the leashes. The aborigines wiped them out in Australia two millennia ago, and bounty-hunting settlers wiped them out in Tasmania by the turn of the last century. By the time conservation efforts were enacted, there were no thylacines to conserve. The likely-female Benjamin, the last known thylacine, died on September 7, 1936, and every year on its death-day, Australia commemorates National Threatened Species Day. The thylacine remains the national symbol of Tasmania, surely the only nation whose coat of arms features an animal it drove to extinction. (Update: Not true. See comments.)

Personal Connection: Or did it? Some people search for UFOs or ghosts or angels or a pair of black pumps under $10. But mythical is mythical. Me, I just want one glimpse of a walking thylacine, and I’m not alone (though shortly after offering that, the Bulletin went extinct too, so make of that what you will). Thylacines have peppered various creations of mine, most notably an unpublished entry for D&D’s Monster Manual III. Someday, when you see my 10th level druid accompanied by a dire thylacine named Stripey, you will know fear.

Other Contenders: the wolverine, whose ascension into comics should come as no surprise; the orca, the killer we call our own; the giant otter, which likes to fish for piranhas; the hammerhead shark, whose gawky appearance proves that nerds can be deadly; the Utahraptor, which will make you forget the overhyped Velociraptor and get down to reading Robert Bakker’s paleo-novel Raptor Red; the osprey, known lovingly around these parts as the “sea hawk.”