This caterpillar is the larvae of the Cape Lappet Moth. Every year they arrive in the garden from October to December. For some reason they seem to love the Brazilian Pepper Trees that are growing in our garden.
The caterpillars seem to gather in large clumps, along the branches, from evening to mid morning when they then disperse to go and find some fresh young leaves to chomp on and then gather again at sunset.
We found this poor guy with host eggs laid all along his back. Apparently the host fly or wasp, injects it’s eggs into the caterpillar and once those larvae hatch they feed on the poor caterpillar and then eat their way out and spin their cocoons on the back of the caterpillar from which the adult host will emerge. So awful but then again that is nature and the law of the wild.