The Bengal tiger
The Bengal tiger beats the African lion hands down when it comes to who’s the hardest. Tigers kill humans because they like to be alone, so invade one’s space and he may well end up having you for dinner. In Sundarbans National Park in Bengal, Bengal tigers kill around 30...
If being agressive towards larger creatures that actually have little interest in you other than as a curiousity just like a Honey Badger does, then i will nominate the Chiwawa.
If not already nominated then i will nominate the Black Mamba