Sparky (also known as Experiment 221) is a villain turned hero from Lilo and Stitch. He appears in Stitch: The Movie.
History
After failing to rescue Jumba from Gantu, Lilo and Stitch decide to consult Jumba’s experiment container to see if there is one that can energize Jumba’s ship,
They settle on Experiment 221, knowing that he is capable of producing electricity.
However, Sparky turns out to be evil, just as Stitch was. He proceeds to escape and causes a power outage.
Lilo and Stitch eventually manage to catch him, realizing that Hamsterviel won’t return Jumba if he is not delivered to him,
They manage to capture him, but Stitch realizes that he and Sparky aren’t so different and bonds with him. Sparky eventually decides to redeem himself and rescues Stitch from Hamsterviel, and makes Gantu’s ship crash into Hawaii.
Afterwards, Lilo decides to have him power up a lighthouse.
Following his reformation, he becomes a recurring character in Lilo and Stitch: The Series.
As with all the other experiments (apart from Reuben, Stitch, and 627), Sparky was captured by Leroy, but was rescued and later fought against the Leroy clones.