Hokkaido Wolf
Wolves are frightening, but imagine what these extinct animals used to be like? The Hokkaido Wolf used to inhabit coastal northeast Asia. They had enormous heads and mouths, with large fangs and teeth. Their claws were three to four times larger than the modern day dog. This isn’t an animal you’d want to take with you on a walk. It would probably eat you.
During the Meiji Restoration period, these wolves were exterminated with strychnine-laced baits. Even though that’s a pretty horrendous way to exterminate an entire species, these animals were probably a threat to humans (Wikipedia).