I came across this caterpillar on the footpath of busy Tooronga Road at East Malvern.
It was dragging its bag across the footpath. I moved it to a safer location.
The caterpillar retreats into the bag when disturbed and I had to wait half an hour each time it got spooked for it to re-emerge so that I could see the caterpillar properly and photograph it.
Here it can be seen crawling over a leaf, still, of course, dragging its bag.