Episode "Yin Yang": Experiments 501 and 502, experiments based of the elements water and fire, respectively, activate at the same time and walk around the island individually, the fire experiment letting loose fireballs and miniature volcanoes while the water elemental sucks up standing water and sprays unsuspecting citizens. David gives Lilo and Stitch a lecture about the co-operative forces of yin and yang in an effort to get the two to work together waxing surfboards. Their rift is further emphasized as they get in each other's ways trying to capture the renegade experiments. Making matters worse, Jumba bets that Stitch will catch the experiments first, while Pleakley supports Lilo. The loser has to perform the 1000-hour long dance, the Glocknar. 625 and Gantu suffer similar teamwork problems, but manage to catch both elementals while Lilo and Stitch end up in a ball of goo as they continue to get in each other's way. But when Jumba remembers that if water and fire should meet, explosions will ensue, Lilo and Stitch have to team up to prevent disaster - until Lilo realizes that maybe, like yin and yang, bringing two opposites together will create positive explosions rather than destructive ones. Episode "Richter": Experiment 513, an earthquake-causing monster is causing tremors all over the island. Nani gets called in on her day off to repair the shake machine, and makes the mistake of bringing Lilo and Stitch along, who only make things worse. Stitch breaks the shake machine and takes the orange ball, which Lilo tells him he needs to learn to take care of. Jumba informs them that if 513 is not stopped, he will locate a major fault line and split the earth in half! Lilo and Stitch chase 513 underground, but a cave collapse cuts them off. They return with a drilling buggy but the cave collapses again and Gantu catches 513. Unfortunately, 513 has set off a chain reaction that can only be stopped with a counter-quake, so Lilo and Stitch sneak into Gantu's base and steal 513 back. Stitch bribes 513 with the orange ball, and it saves the day. Episode ends with 513 becoming employed as they new shake machine at Nani's workplace.