A mysterious monolith that had left onlookers baffled has disappeared from the spot where it was discovered in the Utah desert.

The metal structure was spotted on November 18 by state officials who were using a helicopter to help count sheep.

How it got to its remote spot remained unclear. Despite its mysterious origins, there were claims online that it had shown up on Google Earth as long ago as 2016.

Now, just as curiously, the structure has disappeared, with officials saying its removal was nothing to do with them and instead down to an “unknown party”.

On Sunday (local time), the Utah Bureau of Land Management said the structure, which it described as “private property”, had been removed by “a person or group” on the night of November 27.

Officials never disclosed the monolith’s exact whereabouts but internet sleuths quickly pinpointed its location, leading to some intrepid sightseers making the difficult journey to see it.

The obelisk was about 3-3.7 metres high and was embedded in the red earth.

Helicopter pilot Bret Hutchings, who was among those who discovered it, said it was “about the strangest thing that I’ve come across out there in all my years of flying”.

He told local news channel KSL TV his best guess was it had been put there by a “new wave artist” or a fan of 2001: A Space Odyssey.