The sands of Dee Why beach, north of Sydney, have been transformed into something of a bizarre landscape, covered in green alien balls.
The UFO's - or unidentified floating objects - washed up along the shore leaving locals to ponder what they may be.
Thousands of these balls appeared overnight. They are spheres of around six centimetres across.
Professor Alistair Poore, of UNSW explained: “"They're actually a really unusual growth form of seaweed, because seaweeds mostly grow on the rocks but occasionally they get knocked off and rolled around in the ocean forming these beautiful little balls."
Known is Japan as 'Marumo', they are living organisms that have washed in with the rough weather.
"It's quite an unusual phenomenon, it's only been seen a handful of times around the world,” Professor Poore added.