the moment when some one or something is doing something that doesn't quite tickle your fancy henceforth they are not acting so "pretty" anymore and are "Be'en Ugly" to you it is oftentimes used to express distaste of one's actions. its is a Very colloquial term and not often used by the common populace.
Steve: Yeah dude, do you like my apartment?
Kevin: No way man it looks like a gay guy lives here
Steve: Kevin i hate it when you do this, why are you Be'en Ugly to me?