Spats

 Spats, A.K.A. Experiment 397, is an illegal genetic experiment created by Jumba Jookiba. He is designed to cause any two people zapped to constantly argue with each other. His one true place is making pro wrestlers fight more convincingly. Spats is voiced by Frank Welker.

Bio
Experiment 397 was the 397th genetic experiment created by Jumba with Hämsterviel's funding. He was designed to cause any pair zapped to constantly argue with each other.

397 and the other first 624 experiments were deactivated and smuggled to Earth by Jumba during his mission to capture Experiment 626.

All of the experiment pods were released and scattered across the island of Kauai, with 397's pod landing in the window of Jumba and Pleakley's ship.

Lilo & Stitch: The Series
397's pod was discovered by a squirrel that mistook it for a nut. When the squirrel found it could not eat the pod, it threw it into a bowl of bath bombs. Suga Mama, mistaking the experiment pod for a bath bomb, threw it into the bathtub, activating 397. 397 then zapped the squirrel and Puff, causing the two animals to fight.

397 then zapped many pairs around town, who ended up fighting with each other, including Oscar and Trudy Proud, BeBe and CeCe, Jumba and the hotel inspector, Lilo and Penny Proud, and Gantu and Suga Mama.

Stitch eventually tracked 397 down to a wrestling match, where the two faced off. Penny proud managed to resist her urge to fight with Lilo by counting to ten, and convinced the latter to do the same. Lilo then relieved the other clashing pairs by telling the audience in an amplified voice to count to ten when it looked like one of the wrestlers was down for the count.

397, named Spats, was then captured by Penny Proud and saved from Gantu. The next day, Lilo and Stitch found Spats a one true place making international boxers fight more convincingly.

Leroy & Stitch
The first 624 experiments, including Spats, were round up by Leroy and taken to a stadium to be destroyed. However, Lilo, Stitch, Jumba, Pleakley, Reuben and Gantu arrived before the experiments could be destroyed.

It is unknown whether or not Spats participated in the following battle between the experiments and the Leroy clones.

The Leroys soon gained the upper hand in the battle, but were defeated when Lilo, Stitch, Reuben and several other experiments performed the song Aloha `Oe, which caused the Leroy army to shut down due to the original Leroy's failsafe.

Trivia

 * Spats' pod color is yellow.