An expression inspired by the 2005
internet fad around the Harry Potter and the
Half-Blood prince in which the character
Snape kills Dumbledore.
"Snape killed Dumbledore" is closest in meaning to shit happens or I don't give a shit and is is used as an unsympathetic comeback, similar to Jesus wept.
Guy 1: "Balls. I just failed another
Calc test. Another, and I'll fail
the class."
Guy 2: "Snape killed Dumbledore, you know? You always complain about
failing classes, why don't you study for once?"