And just like that, it was gone: the mysterious steel monolith in Utah, an idée fixe of the internet’s conspiracy-inclined corners since it was discovered last week, has disappeared.

The 12-foot-tall polished block has drawn comparisons to both Minimalist and Land art, and the slab from “2001: A Space Odyssey.” It was spotted earlier this month by officers from the Utah Department of Public Safety (DPS) conducting a count of bighorn sheep in the area. 

Where it came from remains a mystery. But now we have another big question mark with which to contend: Where the heck did it go? Was it surreptitiously recovered by the same aliens who left it there? Or was it snatched by some regular old terrestrials trying to cash in on the fervor?

Upon announcing the discovery last Monday, officials said they would not share the exact location of the object for fear that excursionists may get lost or injured trying to find it. But it didn’t take long for savy Reddit users to track and share its coordinates online.

Visitors to the site uncovered more details about the structure that pointed to humans, not aliens, as its creator. Three rectangular aluminum panels riveted together made up the base, while another triangular panel was secured on top. The object sounded hollow and was not magnetic. Additionally, it appeared to have been silicone-glued into a hole in the earth bed carved out by saw.

A spokesperson for DPS, Lt. Nick Street, told the New York Times that his team was confident it was “somebody’s art installation, or an attempt at that.”

“Somebody took the time to use some type of concrete-cutting tool or something to really dig down, almost in the exact shape of the object, and embed it really well,” Street said. “It’s odd. There are roads close by, but to haul the materials to cut into the rock, and haul the metal, which is taller than 12 feet in sections — to do all that in that remote spot is definitely interesting.”

But as more tourists made their way to the site this weekend, they came across a different site: a pile of rocks where the monolith had previously stood. Only the discarded triangular topper remained.

The DPS confirmed the disappearance in a statement released this weekend, “We have received credible reports that the illegally installed structure referred to as the ‘monolith’ has been removed from Bureau of Land Management public lands by an unknown party.” Officials said it was removed on the evening of November 27.

The state agency also added that it does not investigate crimes involving private property and that such an effort would be handled by the local sheriff’s office.

Numerous artists have been connected with the structure, many of whom—like New Mexico-based artist Petecia Le Fawnhawk and Salt Lake City-based sculptor Dan Toone—have already denied creating it.

But for those keeping track at home, the one that continues to gain traction is Minimalist sculptor John McCracken, who died in 2011.

“The gallery is divided on this,” David Zwirner, who represents the artist’s estate, explained to the Times in a statement. “I believe this is definitely by John.” Meanwhile, McCracken’s son Patrick added his own wrinkle, recalling a moment with his father from 2002.

“We were standing outside looking at the stars and he said something to the effect of that he would like to leave his artwork in remote places to be discovered later,” Patrick told the Times.

“He was inspired by the idea of alien visitors leaving objects that resembled his work, or that his work resembled. This discovery of a monolith piece—that’s very much in line with his artistic vision.”

But the story doesn’t end there. Last Thursday, a similar monolith reportedly popped up in northern Romania. Standing 13-feet-tall, the structure was discovered near a Dacian Fortress in the city of Piatra Neamt.

“It is on private property, but we still don’t know who the monolith’s owner is yet,” a Neamt Culture and Heritage official told the Daily Mail. (Artnet News has not independently confirmed these reports.)