I am assuming this is an insect of some sort. Pupae. It moves around a bit while still being suspended by web from a couple of points. Plus each night the web becomes more complex. Or alternatively it could be a spider with an egg sac.
the paler thing is the egg sack, the darker (horizontal) thing on left (1st picture) is the spider in resting position see also Sighting 4587011 & 4573224
https://www.arachne.org.au/01_cms/details.asp?ID=1827 and this reference shows a spider with an egg sack like yours https://australian.museum/learn/animals/spiders/hackled-orb-weavers/