Oh, oh! I've had TWO instances!! And both were REALLY awkward...
The first, I was just traveling out in the Wastes, and all of a sudden...this BLACK pillar came out from NOWHERE, I mean NOWHERE, and the sky had turned a rainbowy-prism color, and the black pillar was surrounded in a red light.
I knew it was a game glitch, but the thing NEVER went away. But if I went one direction (like the way I came back) it'd disappear...but if I went the OTHER way (the way I was traveling) it'd stay there! Even in the distance, you could see the black pillar stretch endlessly up in to the sky! XDD Cr-AZY [censored] e.o
And another was in Canterbury Commons. The sky had turned red o.o
I was going "OHSHI- OBLIVION HAS INVADED THE CAPITAL WASTELAND" Of course...that would've been bloody awesome, and also terrifying XD But when I looked up a certain angle, it went back to a normal night sky o.o