Topper

Topper, A.K.A. Experiment 025, is an illegal genetic experiment created by Jumba Jookiba. He is designed to use his bright light to pose as a beacon for an invasion to the Galactic Armada. His one true place is as a Christmas star. Topper is voiced by Tress MacNeille.

Bio
Experiment 025 was the 25th genetic experiment created by Jumba with Hämsterviel's funding. He was designed to give off an extremely bright light with which to pose as an invasion-signaling beacon to the Galactic Armada.

025 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
025's pod was found by Gantu on Christmas Eve and sent as a Christmas present meant for Hämsterviel.

However, due to a mix-up, the pod instead fell into the hands of a little girl, and was put in a gift box and giftwrapped. Stitch was the first one to notice the experiment pod, but when he tried to tell Lilo, she ignored him.

Later, in an attempt to find the pod, Stitch stole numerous presents from every house and the local shopping mall on Kauai. After he was confined and interrogated, Stitch revealed to Lilo and the others what he was really trying to do.

When Lilo, Stitch, Jumba and Pleakley located the experiment pod, they had a conflict with Gantu, who was also looking for the pod. Gantu eventually found 025's pod, and then attempted to kill Lilo for her meddling. However, after Lilo lectured Gantu about the true meaning of Christmas, the latter had a change of heart and decided to let everyone in Kokaua Town enjoy 025.

When Jumba discovered 025 to be harmless, Lilo activated 025 in a fountain. She then named him Topper and gave him a one true place atop the Christmas tree (which Pleakley literally became part of) as a Christmas star, while Topper's bright light unintentionally signaled the Galactic Armada.

Topper reappeared in "Elastico" as one of the audience for Lilo's hula dance.

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

Topper 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

 * Topper's primary function is to use his bright light to signal the alien attack fleet. However, on the Disney site, it is incorrectly stated that Topper's light is designed to keep people awake.
 * Even though he was found a one true place on a Christmas tree, it is unknown what he does during the other seasons.
 * Topper's pod color is white.
 * Topper is described by the experiment computer screen as, "Experiment 025 Primary function: Keeper of awakeness to people."
 * His number is likely a reference to Christmas Day (December 25).