"Several Leagues Under the Sea" is the first segment of the first episode of season one from The Marvelous Misadventures of Flapjack. In this episode, Flapjack meets a crazy inventor and brags that Bubbie is faster than a machine.
Flapjack brags that Bubbie is the fastest and accidentally gets her into a race with an inventor who uses boys to power his invention. He fires them all at monsters. Flapjack, feeling guilty, goes back to save them, and Bubbie goes as fast as she can to the finish line. In the end, Bubbie, Flapjack, and K'nuckles win the race. Flapjack learns his lesson about bragging and the episode ends with a robotic version with Captain K'nuckles appearing.
- Two scenes in this episode were censored for Australian viewing, those being:
- The scene when Bubbie was being poked in the eye to eliminate the 'intense' violence, and
- The scene where The Inventor smoked his pipe after telling the children to drip-dry to remove the smoking reference.
- In the original airing of the episode, when The Inventor saw that their scheduled break was over he originally called out "Break time up", for unknown reasons the line was re-dubbed to "Breaks over" in later airings.