Ex Machina

Greek Theater introduced the concept of Deus ex Machina to the world, where a seemingly impossible task would be resolved by the contrived intervention of something newly-introduced to the plot.
On the other hand, Diabolus ex Machina is when something that is absolutely certain is thwarted by the contrived intervention of something newly-introduced.
Theater-goers hate both of these concepts because they demonstrate sloppy writing and planning by the playwright.
But the Japanese love to put both of these machines in an arena full of flamethrowers and buzzsaws and make them fight.
They also like tentacle porn, those weird Japanese freaks.