"The Farnsworth Parabox" is the fifteenth episode in the fourth production season of the American animated television series Futurama. It first aired on the Fox network in the United States on June 8, 2003. The episode was written by Bill Odenkirk and directed by Ron Hughart. The plot of this episode revolves around the Planet Express crew's adventures in parallel universes.

After an experiment nearly kills him, Professor Farnsworth plans to destroy a yellow box containing said experiment by ejecting it into the sun. He forbids the Planet Express staff to open it, and Hermes assigns Leela to guard it. However, she decides to look in the box; she falls in upon doing so and finds herself in a parallel universe.

The parallel Leela orders everyone in the original universe to come into their universe, as the parallel Professor believes that the original universe members are all evil. The two Farnsworths discover that, just as the original Farnsworth created a box containing a parallel universe, the parallel universe Farnsworth created a box containing the original universe. The Professors eventually decide that nobody is evil and the members of the original universe can go back home. However, when parallel Hermes comes in to destroy the box containing the original universe, the crew realize that original universe Hermes must be doing the same thing to the box containing the parallel universe. They plan to go back through the box to stop Hermes but discover that the box is missing. The two Farnsworths try to recreate the original box, but end up creating a large number of boxes containing different universes. As the crew looks through the boxes, the two Zoidbergs walk in holding the original universe box and quickly jump into another universe box, and in the process bump into the bookshelf containing the boxes, causing all of them to fall so the crew are unable to tell which box the Zoidbergs jumped into. Each member of the two crews goes into a parallel universe box in search of them. After checking several parallel universes, they eventually find the two Zoidbergs, and everyone makes their way to the original universe. They arrive outside the box inside the airlock just as Hermes has reached the Sun and is about to eject the box.

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