Mottled Cup Moth ♂ (Doratifera vulnerans)

Also called spitfire caterpillar these can cause a nasty sting from those spines which are everted when the larva feels threatened.
The twisted grey lateral shading indicates that changes are beginning and within the hour this one will form a hardened brown cup around itself in which it pupates. The cup is firmly attached to a eucalyptus stem and looks almost exactly like a gum nut... great camouflage. Another interesting feature of these caterpillars is that they have no legs and move around on a full-length 'foot' rather like a slug.
About 25mm long.
I know this is a male only because I grew it out to adult.
Although these cups are a clever disguise the introduced European wasp decimates them.