The Enfield Haunting (2015)

S1E15 Laughing Fit

After encountering laughing gas in Science class, Team Lyoko finds themselves facing it once more, this time under Xana's influence. While assisting Sissy with a school production of Romeo and Juliet, Ulrich and Yumi inhale the gas, while Jeremie and Odd get a bit too much of it at the factory. This leads to a significant data transfer glitch, leaving Odd barely able to move, let alone fend off Xana’s relentless monsters. With Aelita left to tackle the threat alone and three members of the team in dire straits, will they succumb to laughter?