Weird green light Portugal sky just now

Freakish.

Was smoking a cigar, watching an awl messing with the birds across the street, and suddenly, an green, like neo green light popped up in the night sky out of nowhere!

And then, bang, out, like someone pushed the light button on and off in less then one second.

It was a rectangular shape, very bright green, parallel to ground, but high in the sky. Notice not a single could in the sky tonight, so it wasn't a reflection.

I was facing SouthWest, and higher then any building in my view, so higher then a 7 stores high building - i'm at 5th.

Been looking for a similar image in Google, but can't find any like that - perfect rectangular shape.

WTF??