The plotting and execution of a rambunctious, secret prank on one of your own. Done under cover of nightfall, usually on a Sunday or weeknight. All in good fun, but zingers nonetheless.
Hey, let's Midnight Mission him tonight by hiding in the closets and popping out of them, screeching, when he comes into the room!
She though she was being Midnight Missioned when she heard a knock on her door at 1:30am and saw that her peephole was being covered. However, it turned out that it was just a massive crowd of improvisers.