Art lovers speculated that it was a sculpture by the late Minimalist artist John McCracken. Others were convinced it was an alien marker. Now the shiny, metal monolith that caused a stir after being discovered in the Utah desert last Monday has vanished.

The over ten-foot-tall mystery object was embedded into rock in a remote location. State employees found it while surveying the land for bighorn sheep. By Friday evening, the piece was removed “by an unknown party” from the public land it was found on, said the federal Bureau of Land Management’s Utah office on social media. 

Considered by the agency as "private property," the monolith remains a mystery.