A rare phenomenon known as a fallstreak cloud has been spotted in the skies over Victoria, Australia.
See also: Dramatic 'tsunami cloud' rolls in over Sydney
See also: Rare 'fire rainbow' spotted in South Carolina
Reddit user Big Mac Heart Attack shared the picture online over the weekend, writing: "Spotted this rare phenomenon over eastern Victoria.
"Fallstreak holes, or hole punch clouds, form in clouds that contain supercooled water droplets — at a temperature below freezing point, but not frozen."
A number of users commented on the photograph on Imgur, with one writing: "UFO with cloaking."
Another joked: "Sir, they've seen through our cloaking device!", while another laughed: "I'm expecting conspiracy theorists taking this and running with it. "The govt controls the weather!"
And, right on cue, somebody else wrote: "Pretty sure that's just more government chemical spraying their population into passivity."
According to Wikipedia, a fallstreak hole, also known as a hole punch cloud, punch hole cloud, skypunch, canal cloud or cloud hole, is a large circular or elliptical gap that can appear in cirrocumulus or altocumulus clouds.
Such holes are formed when the water temperature in the clouds is below freezing but the water has not frozen yet due to the lack of ice nucleation.
When ice crystals do form it will set off a domino effect, causing the water droplets around the crystals to evaporate: this leaves a large, often circular, hole in the cloud.
And it looks pretty cool.
This image is included in the Australian Bureau of Meteorology 2016's Australian Weather calendar.