Snafu

Snafu, A.K.A. Experiment 120, is an illegal genetic experiment created by Jumba Jookiba. He is designed to foil enemy plans by any means necessary; he will also ruin any chances of capturing him, and can only be caught by accident. His one true place is with the military. Snafu is voiced by Frank Welker.

Lilo & Stitch: The Series
Experiment 120 was the 120th genetic experiment created by Jumba with Hämsterviel's funding. He was designed to foil any and all plans he discovered at all costs. 120 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.

At an unknown point after this, Experiment 120's pod was found by Jumba and kept in a shoebox under his bed.

Lilo discovered 120's pod in a shoebox when she was searching Jumba's room for any unactivated experiments to use in a rescue mission to free Stitch's cousins.

Jumba warned Lilo not to activate 120 when making a complex rescue mission. However, at that moment, Pleakley entered the room with a hose and sprayed water everywhere, activating 120. The experiment then ripped up the blueprints for Lilo and Stitch's rescue mission and escaped through the pet flap.

120 remained near the house, where he cleverly spied on Lilo, Stitch and the experiments' plans for the rescue mission, and sabotaged their obstacle course.

120 later foiled Gantu's plan to revert all of the experiments to evil by swapping the tape of Angel's song with Gantu's karaoke tape. When the tape was played, everyone on Kauai laughed in amusement.

When Lilo, Stitch and the experiments launched a rescue mission on Gantu's ship, 120 tricked Sample into imitating the ship's alarm to alert Gantu. 120 then rewired the ship's experiment prison, causing it to trap Lilo and the rescue team.

However, 120, named Snafu, did not count on the prison trapping him as well. But after hearing Stitch confess his love for Angel, Snafu cried because it really touched his heart, causing him to turn from bad to good.

Fortunately, Snafu was freed by Angel and Stitch, who also freed Lilo and the captive experiments. Snafu then foiled Gantu before the latter could recapture the experiments, and escaped the ship with Lilo, the rescue team, and the released experiments.

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

It is unknown whether or not Snafu 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 fail-safe.

Trivia

 * Snafu is named for the acronym SNAFU (Situation Normal All Fouled Up).
 * Snafu's pod color is purple.
 * Snafu is described by the experiment computer screen as, "Experiment 120 Primary function: Discombobulates enemy plans."
 * Despite being perfectly unharmed during the events of Leroy & Stitch, Snafu made no attempt or even showed any knowledge of Hämsterviel's plot.