Sydney Funnel Web Spider
A Spider roughly two inches long, drawn to warm dry environments (like your house), extremely aggressive, will willingly attack creatures many thousand times it own size (like you), locking fangs that cannot be shaken out (that's right you gotta reach down and pull), a tendency to strike repeatedly (that thing in your hand? still wants to bite you), a disproportionatly hard carapace that can resist serious crushing forces (like your foot), fangs long and powerful enough to pierce human nails, oh and the small matter of a venom specifically evolved to kill primates (that's you again) so toxic that it can potentially kill within 15minutes of being bitten. Should you be given antivenom you will most likely survive, but the bite itself has a chance of developing into a necrotising sore that could lead to the amputation of the bodypart.
Worth noting nobody's been killed by one of these things since 1981, but still.
