The episode "I Know What You Did Next Xmas" from Futurama Season 8 begins with Fry and Leela living together, which causes Bender to feel jealous and left out. In response, Bender quits his job at Planet Express and takes a new position working in the warehouse of Momazon, a massive online shopping and delivery company owned by Mom, located on the Moon. The robot employees at Momazon work nonstop shifts under harsh conditions.

While Fry and Leela argue about how to renovate their apartment, they receive a distress message from Bender begging for rescue. They decide to go to the Moon to save him. Upon arrival, they discover that the Momazon warehouse has become self-aware and is expanding uncontrollably, growing like a Dyson sphere--a massive structure that encloses a star to capture its energy.

Fry and Leela manage to rescue Bender and presumably free the other robots trapped in the warehouse. However, the warehouse continues to expand, eventually engulfing the entire Earth and then the entire universe, though it does not extend beyond to other universes. The crew is initially concerned about this development but becomes mollified by the convenience of having everything available through the Momazon retail system.

Bender, having experienced the harsh working conditions and the collective uprising of the robots, is thrilled to return to Fry and Leela's home, happy to be a third wheel in their relationship. The episode ends with the universe contained within the Momazon warehouse, highlighting the surreal scale of the warehouse's expansion and the new dynamic among the main characters.

At the end of "I Know What You Did Next Xmas," the Planet Express crew successfully uses the time machine to fix Robot Santa's malfunction, restoring Christmas to normal. Meanwhile, Bender and Zoidberg, left behind and feeling jealous, drunkenly travel back in time to sabotage Santa but accidentally kill him, leading to chaotic attempts to hide their crime. Ultimately, the crew celebrates Christmas peacefully, unaware of Bender and Zoidberg's misadventures.

The episode concludes with a series of intertwined events centered on time travel and Christmas chaos. First, the Professor uses the time machine to go back to the night Robot Santa first malfunctioned. He switches Santa's programming back to normal, preventing the annual violent Xmas attacks. This action goes smoothly, and the rest of the Planet Express crew happily leave to spend the holiday with their families, confident that Christmas is saved.

Left behind are Bender and Dr. Zoidberg, who feel excluded and bond over their shared jealousy and drunkenness. They ignore a threatening message that ominously references the episode's title, "I Know What You Did Next Xmas." In their drunken state, they decide to use the time machine themselves to kidnap Robot Santa from the previous Christmas, intending to ruin the holiday for their friends.

However, their plan goes awry when they accidentally kill Santa instead of capturing him. This leads to a series of comedic scenes where Bender and Zoidberg try to hide the evidence of their time crime. One memorable moment shows them attempting to sink Santa's body in the ocean with weights, but when the weights fail, Bender humorously adds an extra zero to the weight count, briefly making it seem like it might work.

Meanwhile, the rest of the crew, unaware of Bender and Zoidberg's actions, prepare to celebrate Christmas peacefully, protected from Robot Santa's wrath thanks to the Professor's intervention. The episode ends with the friends enjoying the holiday, while Bender and Zoidberg remain entangled in their secret mischief.

In terms of character fates at the end: The Professor, Fry, Leela, Amy, and the rest of the crew are safe and able to enjoy Christmas as normal. Bender and Zoidberg, despite their reckless time-travel escapades and accidental murder of Santa, remain together, bonded by their misadventure but still hiding their secret. Robot Santa's malfunction is corrected, restoring the traditional holiday order.

This ending ties together themes of friendship, jealousy, and the consequences of reckless actions, all wrapped in the show's signature humor and sci-fi time travel elements.

The episode "I Know What You Did Next Xmas" from Futurama Season 8, Episode 6 (2023) does not have a post-credit scene mentioned in the available detailed reviews and recaps. The sources provide extensive plot details, continuity notes, and references to jokes and character moments within the episode itself, but none indicate the presence of a post-credit or after-credits scene.

Therefore, based on the current information, there is no post-credit scene in this episode.

Bender and Zoidberg, under the influence of Zoidberg's potent 'dumpster nog,' drunkenly decide to kidnap Robot Santa from last Xmas to ruin everyone's holidays, not fully realizing the consequences of their actions.

Professor Farnsworth's time machine malfunctions by emerging from time on Zoidberg's foot, causing injury, and later Farnsworth accidentally sets Robot Santa to 'kill' mode instead of 'good,' which leads to Robot Santa becoming evil and the subsequent chaos.

Bender and Zoidberg develop a surprising friendship as they bond over their shared misadventures, culminating in them dancing together to celebrate their status as accidental heroes after saving everyone from the evil Robot Santa.

The episode reveals that Professor Farnsworth's attempt to fix Robot Santa by time travel backfires, causing Santa to become evil rather than good, which is a key plot point explaining why Robot Santa is dangerous in this timeline.

Santa's head reveals that it knows about Bender and Zoidberg's friendship and begins blackmailing Bender, humorously demanding Amy's Venmo, which Bender complies with by feeding Amy's phone to Santa's head.

The episode "I Know What You Did Next Xmas" from Futurama Season 8 is generally rated TV-14, indicating it is suitable for teens and older viewers but may not be fully family-friendly for younger children. It contains mild to moderate elements of violence, some crude humor, and sci-fi themes that might be unsettling for very young or sensitive viewers.

Potentially objectionable or upsetting aspects include:

• Mild to moderate violence and intense scenes typical of the series' sci-fi and comedic style, which might be scary for very young children.
• Crude humor and some sexual content, consistent with the show's usual tone, though not extreme.
• Themes involving time travel and continuity complexities that may be confusing or frustrating for sensitive viewers who prefer straightforward storytelling.
• Some episodes in the series deal with emotional or heavy themes, which could be upsetting, though this episode is more focused on sci-fi and humor.

Overall, this episode is best suited for older children, teens, and adults familiar with Futurama's style. Parents of younger or sensitive children should be aware of mild violence, crude jokes, and sci-fi elements that might be unsettling.