This photo was taken a few days ago (late May 2022, during daylight hours) on a timber deck in the northern suburbs of Melbourne, Australia. The animal is roughly 3cm long. The photograph shows shed fur from a Jack Russell terrier for size comparison.
When a larger animal moves near these insects or they are disturbed, they react by raising their abdomen with its spike in a manner similar to a scorpion. Otherwise, they seem sluggish and slow-moving.
There have been a dozen or so of these insects seen in the area over the last few weeks, but they haven't been seen in previous years.
Given its six legs and segmented abdomen, I'm assuming that it is an insect of some sort.
Can anyone identify this animal?