Gigi

Gigi, A.K.A. Experiment 007 and Yapper, is an illegal genetic experiment created by Jumba Jookiba. She is designed to annoy Jumba's neighbors with her constant yapping. Her one true place is with Mertle Edmonds as her pet. Gigi's vocal noises were provided by Frank Welker, while Tress MacNeille did her speaking voice.

Bio
Experiment 007 was the 7th genetic experiment created by Jumba with Hämsterviel's funding. She was designed to sit, fetch and annoy Jumba's neighbors with her constant yapping.

007 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
At an unknown point, Experiment 007 was activated and adopted by Mertle, who named her Gigi.

In "Yapper", Mertle showed Gigi off to Lilo and Stitch, but when Gigi's yapping began to annoy Stitch, the latter swallowed her whole. Mertle screamed in horror, then dragged Gigi out of Stitch's stomach and took her to a pet salon to get cleaned up.

Later, Mertle revealed that she was entering Gigi in the junior dog show in Honolulu, and called both Lilo and Stitch "riffraff." Hoping to win Mertle's friendship by beating her Gigi, Lilo traveled to Honolulu with Jumba and Pleakley, and entered Stitch in the same dog show, claiming he was a rare blue-furred ectoplasmic detection dog to impress the judges.

Both Stitch and Gigi were entered into all the competitions. However, Stitch's temper (when he fought with another dog after the latter sniffed him) and overconfidence caused him to lose the first two rounds. In the final competition, Mertle secretly gave Stitch extra strong coffee to make the latter go crazy so that Gigi would win.

Mertle's plan was successful at first until Gantu suddenly burst inside the building, sensing a new experiment. Stitch impulsively attacked Gantu, but a stray plasma blast caused the ceiling to collapse on top of Stitch. Gantu then took Gigi from a terrified Mertle, after which she complained to Lilo.

Because Gigi was Stitch's cousin, Lilo promised to save her from Gantu. She then gave Stitch more coffee intentionally, enabling the latter to defeat Gantu and get Gigi back safe and sound.

Grateful but indignant, Mertle gave the "Best in Show" trophy to Lilo. However, when Lilo saw how much Mertle truly cared for Gigi, the former decided to leave Gigi with Mertle.

Gigi reappeared in "Amnesio", being walked by Mertle and the hula girls.

In "PJ", Gigi and a couple of regular dogs attacked Lilo's substitute teacher wearing squeaky shoes shaped like dog biscuits, which was one of PJ's many pranks.

Leroy & Stitch
Gigi was seen being walked by Mertle, the latter stopping to taunt Lilo before moving on.

Later, the first 624 experiments, including Gigi along with Mertle, were rounded 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.

During the following battle between the experiments and the Leroy clones, Mertle with Gigi tried to avoid attacking Leroys. When Mertle and Gigi were saved from a Leroy by Clip, Gigi revealed her ability to speak and her status as an experiment, then pushed Mertle out of the way of a Leroy's plasma blast.

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 fail-safe.

Following the battle, Gigi declared that she wanted to be part of Lilo's ohana, convicing Mertle to join it with Gigi.

Trivia

 * Gigi is one of the ten known experiments named by someone other than Lilo, the other nine being Yaarp, Elastico, Hammerface, Thresher, Heat, Plasmoid, Morpholomew, Shrink, and Leroy.
 * Her episode is named "Yapper" after the nickname Lilo gave her, but she is officially "Gigi" on the experiment name list in Leroy & Stitch.
 * Gigi did not speak in Lilo &amp; Stitch: The Series. However, during the climax of Leroy & Stitch, it is revealed that she can speak English very well and says to Clip, "Nice one, cousin." She then says to Mertle, "Look out!" and pushes her out of the way of a Leroy's plasma blast.
 * Gigi's pod color is white.
 * Gigi is described by the experiment computer screen as, "Experiment 007 Primary function: Annoying with barking forces."
 * Gigi's number is a reference to the secret agent number of the legendary James Bond.