Monkeys flying

Okay, why would you come up with "when pigs fly" as a phrase for impossible things and then turn around and make it worse by taking it to the next level with "when monkeys fly out of my butt." In the movie, Bruce Almighty, they actually make a monkey fly out of a guys butt. Well actually, it doesn't fly. I think the Wizard of Oz has the copyright on flying monkeys. But you get my point, don't you?

I mean, monkeys don't go around talking about humans flying out of their butts. We take our butts seriously. So humans, stay off and out of my butt.