You will Watch Code Lyoko Episode 15 online for free episodes with HQ / high quality. Stream cartoons Code Lyoko Episode 15 Laughing Fit In class, Mrs. Hertz is teaching the class about nitrous oxide, more commonly known as laughing gas, and its effects. It can be dangerous if not neutralized by water quickly. Meanwhile, Yumi’s parents are having trouble with their relationship, which Yumi isn’t too happy about. No one can seem to cheer her up, even Ulrich. He eventually manages to do so, however, and helps her find a way to bring her parents back together. During a school production of Romeo and Juliet, Xana possess the laughing gas in the science room and uses it to attack Odd, who is doing the music.