“It is illegal to install structures or art without authorisation on federally managed public lands, no matter what planet you’re from,” warned the agency in a tongue-in-cheek press release on Monday.

News of the discovery quickly went viral online, with many noting the object’s similarity with strange alien monoliths that trigger huge leaps in human progress in Kubrick’s classic sci-fi movie 2001: A Space Odyssey.

Others remarked on its discovery during a turbulent year that has seen the world gripped by the Covid-19 pandemic, and optimistically speculated it could have a different function entirely.

“This is the ‘reset’ button for 2020. Can someone please press it quickly?” joked one Instagram user.

“Up close it reads: ‘Covid vaccine inside’,” wrote another.

With officials refusing to disclose the object’s location out of fear that hordes of curious sightseers would flock to the remote wilderness, a race has also begun online to geolocate the “obelisk” using surrounding rock formations.

Bret Hutchings, the pilot who happened to fly over the obelisk, speculated that the obelisk had been planted by “some new wave artist”.

Some observers pointed out the object’s resemblance to the avant-garde work of John McCracken, a US artist who lived for a time in nearby New Mexico, and died in 2011.

“While this is not a work by the late American artist John McCracken, we suspect it is a work by a fellow artist paying homage to McCracken,” a spokeswoman for his representative David Zwirner said.

Either way, Hutchings admitted it was “about the strangest thing I’ve come across out there, in all my years of flying”.

“We were kind of joking around that if one of us suddenly disappears, then the rest of us make a run for it,” he told local news channel KSLTV.