An ice-block is a cold, sweet treat on a stick. Made from a water base or an ice-cream base they are also known as popsicles in other parts of the world.
Ironbark is a type of gum tree (Eucalyptus species) and like all gums native to Australia. The ironbark is different to a lot of gums in that it doesn't shed its bark annually. Instead the bark accumulates and provides protection for the tree from fire.
The irukandji is a tiny jellyfish (2.5cm/1" diameter) found in northern Australian waters. Although tiny it can cause the death of a person in a matter of days (the first recorded death was in 2002). The irukandji is related to another deadly Australian jellyfish, the box jellyfish.