Protovampirus

Protovampirus is an extinct species of bat that lived in what is now the European island of Sicily during the Late Oligocene to Early Miocene. It resembled very much like a former fictional Night Stalker from After Man series, but with visible and functioning eyes used for sight unlike most other bat species, which relies on echolocation with their ears, and much smaller and more pointed ears due to losing its echolocation function. It was a carnivore that fed on wide variety of smaller animals such as rodents, mustelids, moles, early hedgehogs, fallen modern-styled bats, carrion, eggs, birds, small reptiles, frogs, fish, and large insects, and spiders. It was about twice the size of a modern day wolverine, but more vicious and more dangerous due to its slightly larger intelligence (almost as smart as a parrot) and stronger jaw strength. It was a bipedal mammal with a unique locomotion, having to walk on its front legs while keeping its back legs off the ground, as its back legs were likely used to grab its prey items. No one knows why this animal became extinct in reality, but in the different universe, its descendants had survived and evolved into a larger man-like blood-sucking infectious predator that walked very human-like (unlike its ancestors) known as a vampire, which were brought into real life.