What are the three poisonous Australian creatures?

Answer 1

There are a lot more than three.

Australia is home to seven of the worlds ten deadliest snakes. The top 3 are the Taipan, the Death Adder and the King Brown (or Mulga snake). These are known by some as "3 minute snakes" because that is supposedly how long it takes for the venom to kill.

There are two Australian Spiders capable of delivering fatal bites, being the Funnel Web and the Red Back.

The Blue Ringed Octopus has a lethal venom and there is no known antidote.

The venomous beastie that is responsible for most deaths in Australia is the European Wasp, averaging ten fatalities per year nationally.