Glitch

 Glitch, A.K.A. Experiment 223, is an illegal genetic experiment created by Jumba Jookiba. He is designed to act as a computer virus and cause invaded technology to turn on its owners. His one true place is in Lilo's portable game console. Glitch is voiced by Frank Welker.

Bio
Experiment 223 was the 223rd genetic experiment created by Jumba with Hämsterviel's funding. He was designed to invade technology like a computer virus and cause it to turn on its owners.

223 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.

Lilo & Stitch: The Series
223's pod eventually made its way to a baseball pitching machine, where it was used as a softball. While the machine went haywire, the experiment pod was batted away by Slugger and flung onto the Lick-o-matic at the Pelekais' house. The Lick-o-matic, mistaking the pod for a stamp, licked it, activating 223.

223 then took over the Lick-o-matic and caused it to throw tomatoes at Pleakley. 223 then passed through the house's power lines and into the main computer, from where he took over all of the house's technology.

223 then locked the entire house down, trapping the occupants, whom he picked off one by one.

When Jumba discovered that Experiment 223 had taken over the house's main computer, 223 locked the former in the bedroom, then later trapped Nani in the attic and Pleakley under the couch.

223 targeted Lilo and Stitch next. However, they were able to download 223, named Glitch, out of the computer system and into Lilo's portable game console, thus trapping him.

Leroy & Stitch
The first 624 experiments, including Glitch, 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 Glitch 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.