https://gizmodo.com/unexplained-monolith-discovered-in-rural-utahs-red-rock-1845745303
Obviously a brilliant prank, but a bit odd given the remoteness/likelihood it could have been a long time before being discovered. Maybe the artist was hoping it wouldn't be found for years or decades, perhaps bringing fame long after their death?
Doesn't appear to be any easy task to have done the installation. Probably required a good bit of help and money.