Giant wood moth, Endoxyla cinereus, Cossidae. Found in Australia.

Giant wood moths can have a wingspan of around 23 centimeters. Larvae are wood borers, and along with other similar species, are commonly referred to as witchetty grubs. An interesting twitter thread here explaining how the term witchetty grub was derived from an indigenous term

Photos 1-2 by jessster78, 3-5 by questagame, 6-7 by vicfazio3, 8 by rqy-yong, 9 (larvae) by Sputnikcccp, and 10 (pupa) by orlandob