Slick is a fast-talking, Southern-accented salesman. He is generally very friendly and polite, tipping his hat every time he greets somebody, but is quite obsessive about selling stuff. He won't stop doing so until there is nothing left to sell, even selling himself to Mertle through a live auction. He is also very kind-hearted and courteous, and strongly supports his one true place in working for charity.
Despite being incredibly friendly, Slick can also be amazingly fierce. This was shown during the climactic battle in 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. Thus, he can easily turn from a friendly salesperson to a terrifying fighter, while still keeping his good intentions.
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. According to Jumba, 020 once sold the former's wife for an outrageous price. 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 candy bars for a fundraiser at their hula school, and encountered 020 reading a newspaper while sitting on a park bench. When 020 heard Lilo and Stitch's predicament, he introduced himself to them and presented his card that revealed his number and primary function.
020, named Slick, then offered to assist Lilo and Stitch in their fundraising drive. Using his sales pitch, Slick managed to convince every person whom Lilo came across into buying one of her chocolate bars.
However, Slick later grew obsessive and began selling everything the Pelekais owned. Since they were unable to capture Slick (as he had sold all their containment orbs as well), Lilo left Pleakley in charge of Slick while she and Stitch set out to redeem all of their personal belongings. Among one of them was a trophy that a couple was using to stabilize an outdoor dining table.
While they were doing this, Mertle, who found out about Slick earlier, showed up at the Pelekais' house looking for the salesman experiment. Annoyed, Pleakley tried getting Mertle to leave, but Slick, unwilling to just turn down a customer, allowed her to come in. When both of them declared custody of Slick, the latter held an indoor auction and set the opening bid at one dollar. The auction ended with Slick selling himself to Mertle for three dollars.
After managing to retrieve all of their household possessions, Lilo and Stitch returned home to discover that Slick was gone. Pleakley explained what happened, prompting Lilo and Stitch to get Slick back.
Meanwhile, Mertle used Slick to solicit candy bars and help her win the contest until Lilo and Stitch stole him, but Mertle managed to steal him back. Later, when Lilo and Stitch (disguised as beekeepers) went over to Mertle's house to reclaim Slick, she revealed that she had sold him to Experiment 625, much to their horror.
At Gantu's ship, Slick acquainted himself with Reuben and later sold the ship to an old man, who had somehow gained entry. Slick was soon after captured in a container by an ailing Gantu, who had been repeatedly persuaded by Hämsterviel to do so.
Fortunately, Lilo and Stitch arrived and managed to rescue Slick, but Gantu was able to track him down and recapture him. However, Gantu ultimately traded Slick for Lilo's last chocolate bar, claiming it would cure his cold.
Shortly after, Slick found his one true place at Lilo's school in raising money for charity.
In "Remmy", Slick was one of the experiments in Lilo's dream.
Slick was one of the experiments that was gliding on the screen, but he is 597 instead of 020.
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 ʻOe", which caused the Leroy army to shut down due to the original Leroy's fail-safe.
- Slick is very similar to Swamp Rat from 101 Dalmatians: The Series in that both are salesmen and both speak with a fast-talking Southern accent. The only difference is Swamp Rat is more of a con artist. Coincidentally, both Slick and Swamp Rat's voices are identical, and both even share the same voice actor, Jeff Bennett.
- Like Reuben, Slick is one of the very few known experiments that can speak English rather fluently.
- Slick's pod color is red.
- Slick is described by the experiment computer screen as, "Experiment 020. Primary function: Salesman."