noun phrase. The shittiest of all plot twists.
Real citation: "A weekly series, though, needs a story to go with its characters, and 'The Mentalist' is undone by the same poo ex machina storytelling that makes other CBS procedurals so unwatchable."
(Sept. 22, 2008, Glenn Garvin, Catholic Online, http://www.catholic.org/ae/movies/review.php?id=29563)
Made-up citation: "I didn't like the poo ex machina in Avatar. Isn't it convenient that a giant turd just happened to kill all the evil smurfs!"