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Code Lyoko Wiki

Lab Rat is the thirteenth episode of Season 4 and the seventy-eighth episode of Code Lyoko.


In the cafeteria, Jeremie announces to Ulrich, Odd, and Aelita that he has found a way to materialize them onto Earth from a Replika in the vicinity of the supercomputer generating it. After breakfast, the group meet up with Yumi outside the cafeteria, where Jeremie and Aelita relay the news to her and add that they plan to test Jeremie's idea that night. However, when Ulrich attempts to ask her about something, Yumi acts coldly and walks away.

Odd, stunned by what happened, asks what he did to earn such a cold reaction. Ulrich says how he has no idea, but that it began the day before yesterday. Odd reveals how Yumi's birthday was on that date, and Ulrich realizes he forgot about her birthday. Odd brings up how important such days are to Yumi and Ulrich thinks she'll likely be mad at him for weeks. Ulrich wishes to immediately go buy her a late birthday present as an apology, but realizes he can't since he has detention for a prank he was blamed for by Jim. Odd then offers to buy the gift for Ulrich since he was planning to head into town to buy a new toy for Kiwi anyway, and the prank Ulrich was punished for was actually done by him and he owed him for it.

That evening, the Lyoko Warriors meet at the Factory, and Odd discreetly gives Ulrich Yumi's wrapped gift, but refuses to say what it is with the genuine assurance that she'll love it. Ulrich decides not to give Yumi the gift right away, and she remains aloof as they are sent to Lyoko and board the Skid. Aelita then pilots the Skid out of Lyoko and into the Digital Sea, where she uses a Hub to get to the Forest Replika.

When the group enters the Replika, Jeremie detects an activated tower there to which Aelita indicates that X.A.N.A. is active somewhere on Earth very close to the vicinity of the supercomputer generating the Forest Replika. Aelita then moors the Skid to an inactive tower, which Jeremie activates for their own use. Jeremie successfully translates Odd and Aelita to Earth while Ulrich and Yumi disembark from the Skid to stand guard.

Odd and Aelita find themselves in the Amazon Jungle, and discover they have retained their Lyoko avatars and powers. Jeremie explains that they are essentially spectres similar to ones X.A.N.A. uses, and reveals that they only have a limited amount of time on Earth. Aelita notices the laboratory containing the supercomputer beyond a cluster of trees and foliage so she and Odd begin walking toward it.

Meanwhile, Ulrich is desperately trying to earn Yumi's forgiveness, repeatedly apologizing for forgetting about her birthday. However, Yumi tells him how she has never forgotten his birthday and refuses to accept his apology. Suddenly, Ulrich and Yumi are confronted by William and three Tarantulas, and a battle ensues. Yumi takes on the monsters while Ulrich engages William. In the jungle, Aelita and Odd manage to infiltrate the laboratory, where they find all the scientists inside are possessed by X.A.N.A.. They then find a room containing a vivarium full of robotic spiders before being discovered by one of the possessed scientists and a fight breaks out.

On the Replika, Ulrich is devirtualized by William as Yumi defeats the last monster. Yumi uses her fans to defeat William but he manages to catch them and turn them into a black smoke utterly destroying them, leaving her defenseless. As Yumi dodges William's attacks, Aelita and Odd defeat the scientist in the laboratory and find the supercomputer behind a locked door. Aelita uses her Creativity to open the door, but they then discover the supercomputer is guarded by some sort of force field.

Jeremie manages to virtualize a new pair of fans to Yumi, but before she could even get another chance to fight, she is immediately devirtualized by William, who then proceeds to enter Jeremie's tower. Odd is able to destroy the shield protecting the supercomputer just as William enters the X.A.N.A. code into the tower, severing the Skid from the tower and forcing Odd and Aelita back to the Replika before they can destroy the supercomputer itself. Aelita pilots the Skid out of the Replika under laser fire and returns to Lyoko.

Later, the Lyoko Warriors convene in the lab, where they discuss the failed mission. As the group leaves the Factory, Ulrich stops Yumi on the bridge and gives her the gift. Yumi finally forgives Ulrich for forgetting her birthday and kisses him on the cheek, leaving him blushing. Aelita looks on saddened as she's unable to remember when her own birthday is. Jeremie tells her to simply pick a date herself as her birthday. However, Aelita asks Jeremie to pick the date for her. He does so, but won't tell her when the date is, wanting it to be a true surprise for her.

After returning to their dorm, Odd opens the box containing Kiwi's new toy while Ulrich watches, but finds a necklace instead. It is then revealed that Odd accidentally switched the gifts and gave Yumi the box with Kiwi's toy in it instead of the one containing the necklace. Meanwhile, in her room, Yumi unwraps her gift and finds a squeaky rubber bone, much to her confusion.


  • The original French name of this episode is Expérience.
  • This was originally episode 75 chronologically during the scripting phase.[1]
  • This episode did not air in the United States for unknown reasons, nor was it released on Cartoon Network's website. The English dub of the episode wasn't ultimately released until August 21, 2008 on Kabillion, making it the last episode of the dub to premiere.[2]
    • Because of this, this is the first out of eight episodes to not air on American television and instead be released online, and the only one of these episodes not to be released on Cartoon Network's website.
    • This version notably used the Season 1 opening sequence instead of the Season 4 opening. This was fixed when the episode was uploaded to the Official YouTube Channel.
  • Yumi turned 16 two days prior to this episode, revealing her birthday is somewhere in the first half of the French school year.
  • This episode marks the first time in the series someone other than Aelita (or her possessed self) travels to the second floor of a tower and inputs a code.
  • In the scene where Ulrich lets go of Odd after the bell rings, Milly can be seen in the background in her Seasons 1-3 outfit instead of her Season 4 attire.
  • When Jeremie says they have thirteen minutes, there are thirteen minutes left until the end of the episode (end credits included).
  • Jeremie technically already has picked out a birthday for Aelita, since he is the one who forged all of her ID papers and health records.


  • When Milly passes by in the background she disappears behind Ulrich, not appearing afterwards.
  • Avatars in the real world do not look quite the same as they do in a virtual environment. Most noticeably, Aelita's avatar does not have pointed ears.
  • Aelita's earring is missing from her left ear at various points while she is in the laboratory, and it switches to her right ear at another point.
  • After William causes Odd and Aelita to teleport back into the Skid from the laboratory, Odd is standing in his Nav Skid but in a position such that his body is parallel to the ground of the Forest Replika. He should be aligned perpendicular to the ground because the Skid did not change orientation after being disconnected from the tower.



  1. "From scripts to episodes S4 - Part 1 -
  2. "S4 Episode 13: Lab Rat". August 21, 2008.