The bizarre black-shaped object seen in the photos, released online, is suggested to have appeared through “a wormhole or portal” in clouds above El Pasco, Texas, US.

A series of conspiracy and counter-conspiracy theories – including that it is a “sign of the devil” or a “US Government hologram to test human reaction ahead of a genuine alien disclosure” – have now sprung up across the internet.

One theorist posted online: “There’s no doubt at all that this is real and this is actually very concerning too because it’s come through a wormhole or vortex meaning this craft has come from anywhere and it does look very sinister indeed.

“My personal opinion is it’s a scout ship and more could be coming soon. Could this be a precursor to an alien invasion of Earth?”

Gregg Prescott, editor of the In5D spiritual website, warned the cube was linked to the devil.

He said: “If this is a real, cube-shaped UFO, then it probably is not here in humanity’s best interests based on my research of the cube and its ties to Saturn/Cronus/Satan.

“Most likely, it’s some elaborate hoax, a marketing ploy, a hologram, or a PSYOP [psychological operation] designed to classically condition our minds in preparation for an ‘official’ UFO disclosure.”