007. Destroy Humanity - Moonraker
The Plan: Hugo Drax is a billionaire who wants to wipe out all people on Earth and replace them with his own hand-picked "master race." So he somehow constructs a space station without anyone noticing, then transports his perfect people to it. His scientists have developed a nerve gas that is fatal to humans, but harmless to plants and animals, and he prepares to launch globes full of it at the surface. Once the gas has cleared, he and his people shall inherit the Earth!
The Idiocy: Say, where
do you find a whole cadre of minions willing to help you kill billions of people? I want to know. That's just one of many, many, many logistical concerns that arise when you consider the sheer mechanics of pulling off a plot like this. Really, though, I guess this movie shot any pretense that it wasn't a cartoon cash-in on
Star Wars in the head with the sequence where a space shuttle takes off from the back of a plane. This plot is on the list due to sheer absurdity, while it's the lowest simply because it still manages to seem more sane than what comes next.