Usually refers to God (or Jesus) without actually naming Him. (The Man upstairs.)
In general, alludes to the boss, the man in charge, upper level supervision, a member of management, or the executive decider.
"SOMEONE UPSTAIRS must like me 'cause I pulled through that rut like a miracle."
"Better cover your ass, boi. SOMEONE UPSTAIRS is gunnin' for you."
"I'm sorry, ma'am but that decision is for somebody above my pay grade. I'll have to refer this matter to SOMEONE UPSTAIRS."
This is when you wake up in the morning feeling like you really tied one on the night before even though you didn't have anything to drink. Through some sort of karmic mixup, you woke up with someone else's hangover, and they woke up feeling like a champ.