There seem to be some seriously weird things in Oz
We have more than our fair share, there's not much that will eat you (none if you stay out of the water like any sensible person would) but a lot of things that will bite.
doesn't one of the spiders have fangs that can actually penetrate a shoe or is that a myth?
It's probably a myth but this little fella would come close.
There is also a tiny octopus that can kill an elephant
That would be the blue-ringed octopus, only a couple of inches in size but (I think) one of the deadliest critters anywhere. How they tested one on an elephant I have no idea 
Rob