This is a male Sydney funnel-web spider, Atrax robustus. Look at those freakin’ fangs! Holy Jesus!
It is exceptionally venomous in it’s bite. The venom can kill a person within 15 minutes. That is obviously not a good thing.
The bad news is the that it is currently projected to imminently become a major invasion-level problem for Australia now that the rains are wetting up everything after the ordeal of the horrific heat and fires.