I saw iridescent green ufo 'saturn' shaped hovering over the 3 story apartment block.

On the evening of Monday 9 January around 8.15pm I stood on my front landing and watched an iridescent green ufo of the classical style (saturn shaped) hovering above the 3 story apartment block across the road. It hovered about 6 feet above the building.
The ufo was about 1.8 meters in diameter. And appeared to pulsate in and out of reality.It had no other lighting. This vehicle was totally green and had no portholes around the dome rather there appeared to be a black lattice work on the dome.  As for overall size perhaps the size of a old VW car.
It hovered for about 5 mins. I felt it was making sure I was able to get a good look at it, but I did not dare go inside to get a camera as I was worried it would disappear. When it did move it zapped straight down to the water front which is about 200 metres away. It then hovered at the waterfront. I do know that there is a wading pool down there so it could have been looking at the water source. It then just zapped out across the horizon. As it disappeared it turned a grey colour but that could have been cloud covering.
As a unversity researcher with a PhD in Law I am writing about space law and protocols for engagment with extraterrestials. I texted my brother as soon as the incident happened. He is a senior public servant and flies small drones. He indicated it did not sound like a drone as the lighting was incorrect and it is against the law to fly drones at night in Australia. Also hobby drones are not that large.