Slick

Slick, A.K.A. Experiment 020, is an illegal genetic experiment created by Jumba Jookiba. He is designed to sell anything to anyone, using the tactics of a professional salesman. His one true place is selling for charity and fundraisers at Lilo's hula school. Slick is voiced by Jeff Bennett.

Personality
Slick is generally friendly and very polite, tipping his hat every time he greets somebody, but is very obsessive about selling stuff. He won't stop selling things until there is nothing left to sell, even selling himself to Mertle through a live auction. He is also very kind-hearted and strongly supports his one true place working for charity.

Despite being incredibly friendly, he can also be amazingly fierce. This was shown during the final battle from Leroy & Stitch. His initial facial expression after Stitch's pep talk was fearsome, and at one point during the battle, he had a Leroy clone running from him. So, he can easily turn from a friendly salesman to a terrifying fighter while still keeping his good intentions.

Lilo & Stitch: The Series
Experiment 020 was the 20th genetic experiment created by Jumba with Hämsterviel's funding. He was designed to sell anything, including other experiments, to unsuspecting victims. 020 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 020 was activated.

Lilo and Stitch were having trouble selling chocolate bars for a hula halau, and passed 020 sitting on a park bench reading a newspaper. When 020 heard Lilo and Stitch's problem, he introduced himself to them and presented his card, which explained his primary function.

When Lilo and Stitch discovered 020's powers, they took him in and used him to try and sell candy bars. Using his sales pitch, 020 managed to convince every person that Lilo came across into buying one of her chocolate bars.

However, 020, named Slick, eventually began selling everything the Pelekais owned. Fortunately, Lilo and Stitch managed to reclaim all of their household items before it was too late.

When Mertle noticed Slick, and learned that he was a master salesman, she and Lilo competed for ownership of the experiment. Intrigued, Slick held a live auction at Lilo's house, which ended with Slick selling himself to Mertle. She then used Slick to solicit candy bars until Lilo and Stitch stole him, but Mertle managed to steal him back.

Later, when Lilo went over to Mertle's house to reclaim Slick, Mertle told Lilo that she sold Slick to Experiment 625, much to Lilo's horror.

At Gantu's ship, Slick chatted amicably with Reuben until the former was eventually captured by a sick Gantu, who had been repeatedly persuaded by Hämsterviel to do so.

Fortunately, Lilo and Stitch managed to rescue Slick, but Gantu was able to track him down and recapture him. However, Gantu ended up trading Slick for Lilo's last chocolate bar, claiming it would cure his cold.

Shortly after, Slick found his one true place in raising money for charity.

In "Ploot", Lilo tried to convince Slick to help her defeat Ploot, but he led Lilo astray by trying to get her to buy a Kokaua Town umbrella.

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

The Origin of Stitch
Slick was one of the experiments that was gliding on the screen, but he is 597 instead of 020.

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

Slick participated in the following battle between the experiments and the Leroy clones, having frightened at least one Leroy clone.

However, 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

 * Slick's pod color is red.
 * Slick is described by the experiment computer screen as, "Experiment 020 Primary function: Salesman."