Weird appearing and disappearing monolith. Any theories? Aliens?

[leavethelightson]

First it appeared in the Utah desert, then just as weirdly as it appeared it disappeared.

Now a similar one has appeared in the middle of nowhere in Romania.

So, a door to an alien world? Is this how 2020 turns out?!

Oops I meant AD campaign not Adult

Another one has appeared today, this one is on the Isle of Wight! Apparently it's a bit smaller, around 7ft tall, so was probably easily transported in the back of a car (rather than an alien spaceship, borrowed by alien teenagers to play a joke on earthlings during their gap year).