Weird Science (1994)

S4E25 Swallow 13

Chett accidentally swallows a rare invitation with directions to an underground rave. In a bid to retrieve it, Lisa shrinks herself, Gary, Wyatt, and a spaceship. They embark on a journey inside Chett, reminiscent of "Fantastic Voyage," witnessing far more of him than they ever wanted. Meanwhile, Chett's girlfriend, Sharon, decides to break up with him, leaving Wyatt with Post Miniaturization Stress Syndrome, which drives him to sabotage their mission. As chaos ensues and the ship runs low on oxygen, Lisa and Gary must find a way to make the emotionally distant Chett cry, or risk being trapped inside him forever.