"Reincarnation" (originally titled "Resurrection") is the 26th and final episode of the sixth season of the animated sitcom Futurama. It originally aired on Comedy Central on September 8, 2011. This is the only episode not to be animated in its regular animation, instead featuring three different segments, each segment showcasing Futurama "reincarnated" in a different style of animation. The plot of each segment forms part of an overall story arc, revolving around the discovery and subsequent destruction of a Diamondium comet. A running joke for the episode involves a key plot point in each segment being obscured by the specific animation style, though the characters themselves express amazement over what they see.

The episode was written by Aaron Ehasz and directed by Peter Avanzino. Stephen Hawking guest stars during the second segment.David Herman voices Professor Farnsworth in the third segment, in place of regular voice actor Billy West.

Prior to the episode's triptych structure, a brief introduction is given by the God entity from the 2002 episode "Godfellas"; "A wise man once said that nothing really dies, it just comes back in a new form. Then he died. So next time you see a lowly salamander, think twice before you step on it. It might be you. Stand by for reincarnation".

The first segment is animated in a 1930s black-and-white "Fleischer and Walter Lantz style". Professor Farnsworth discovers a comet made of Diamondium, the hardest substance in the universe, and sends the crew to gather diamond dust from the comet's tail to polish a doomsday device. Fry sneaks onto the surface of the comet and finds a large gem, which he hopes to give to Leela as an engagement ring. Fry plants the Professor's doomsday device on the comet and brings Leela to the balcony of the Planet Express building, thinking the resulting explosion will dislodge the gem and send it flying to land on her finger. It instead splits the comet in half, with one half flying towards the sun and creating a rainbow, and the other half flying into the rainbow and creating an entirely new color. Leela marvels at the beautiful sight, depicted entirely in grayscale. Before Fry can propose to Leela, the comet crumbles to dust that falls onto the Planet Express building, crystallising and trapping Fry and Leela in a giant diamond. One billion years later, an alien proposes to his alien girlfriend with a ring containing the diamond in which Fry and Leela are trapped.

...
Wikipedia