Dark-matter afterburner

The dark-matter afterburner was created by Professor Hubert J. Farnsworth so the Planet Express ship could deliver 200% fuel efficiency. The idea for it came to him in a dream but was lost in another dream. The Professor showed the device to his son, Cubert J. Farnsworth, who thought that it was "especially impossible" to function. As of 3008, the dark-matter afterburner has been using whale oil, the new starship fuel.

Trivia

 * Getting the idea for an invention in a dream is a reference to the  movies.