Yaarp

Yaarp, A.K.A. Experiment 613, is an illegal genetic experiment created by Jumba Jookiba. He is designed to create devastating sonic blasts from his megaphone-like head. His one true place is at Lilo's hula school as an alien invasion alarm and buzzer. Yaarp is voiced by Jeff Bennett.

Personality
Yaarp is very friendly, but responds quickly and dramatically to the way he is treated. For example, if he feels intimidated or provoked, he will emit loud sonic blasts. If he feels safe or unthreatened, he will emit small, gentle honks as a sign of trust and affection.

Yaarp, for the most part, is pretty simple and laid-back. However, he is very ready-minded and cautious. Yaarp is a bit jumpy and nervous, sometimes sounding his horn at improper times because something trivial startled him.

Lilo & Stitch: The Series
Experiment 613 was the 613th experiment to be created by Jumba with Hämsterviel's funding. He was designed to use his sonic blaster to shatter buildings and deafen nearby victims. 613 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, with 613's pod landing in Mrs. Hasagawa's fruit.

When Mrs. Hasagawa watered her fruit, 613's pod got wet, activating the experiment.

613 then proceeded to cause massive chaos using his destructive shock waves.

When 613 was later chased by Gantu into a store, the former was captured but freed by Stitch. This unintentionally allowed 613 to escape, but not before emitting a sonic blast that caused Stitch to temporarily go deaf.

Realizing how clever 613 was, Lilo decided to hire Pleakley to try and capture the experiment. After some training and conditioning from Lilo, Stitch and Jumba, Pleakley was ready to track down 613.

Meanwhile, Gantu resumed his search for 613. Stitch disguised himself as the experiment and acted as decoy to fool Gantu, while Lilo, Jumba and Pleakley searched for 613.

613 retreated to a cave, where he was eventually discovered by Pleakley. When Pleakley unintentionally blasted 613, the latter retaliated using a massive shock wave. However, when a sudden cave-in endangered 613, he was then saved by Pleakley. After 613 kissed Pleakley for saving his life, the latter christened him Yaarp.

Pleakley and Yaarp then fled the crumbling cave and made it out safely. Yaarp growled when he first saw Lilo until Pleakley assured him that she was a friend. Unfortunately, Stitch was captured by Gantu (who thought Stitch was Yaarp) during the process.

As part of a setup, Yaarp was taken to the local museum for a ransom exchange. When Lilo and Yaarp arrived there, the former tricked Gantu into believing that Yaarp was rehabilitated before making the ransom. However (as planned), when Gantu removed his earplugs, Yaarp unleashed a sonic blast which set off an alarm, alerting the authorities and forcing Gantu to flee.

Yaarp, after being revealed to the authorities, was shortly after given a one true place as an alien invasion alarm at Lilo's hula school.

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

Yaarp reappeared in "Spike" for the Ohana-Rama. He was the scorekeeper for the contest.

In "Remmy", Yaarp was one of the experiments in Lilo's dream.

Leroy & Stitch
In the film's opening Yaarp can be seen greeting Lilo with sonic blasts from his horn.

Later, the first 624 experiments, including Yaarp, 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.

Yaarp 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. Yaarp joins them for the song by playing the built-in horn on his head.

Trivia

 * Yaarp is one of the ten known experiments named by someone other than Lilo, the other nine being Gigi, Elastico, Hammerface, Thresher, Heat, Plasmoid, Morpholomew, Shrink, and Leroy.
 * Yaarp's pod color is yellow.
 * Yaarp is described by the experiment computer screen as, "Experiment 613 Primary function: Noisemaker."
 * Yaarp's torso and tail appear in the game Jumba's Lab.