Finder is a very beneficial and resourceful tracker who has a knack for uncovering any missing person or thing. Unlike most experiments, Finder does not cause chaos or mischief with his powers. However, he is a bit competitive as shown when he and Stitch argued over which direction to go while attempting to track down an escaped Hämsterviel. Aside from this, Finder appears to be very calm and collected when finding lost individuals or items.
Experiment 158 was the 158th genetic experiment created by Jumba with Hämsterviel's funding. He was designed to track down and detect any missing person or item. 158 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 158 was activated.
Finder demonstrated his powers by finding Nani's missing keys in the fridge, which made Stitch envious. The latter then attempted to outdo Finder by shredding the sofa cushion and uncovering a few buried items. However, Lilo concluded that Finder was better at finding stuff than Stitch.
The Grand Councilwoman later contacted Jumba and Pleakley about Hämsterviel, who escaped from prison and traveled to Earth. Finder was assigned to track down the fugitive, but a competitive Stitch set out to upstage Finder by beating him to the punch. When both cousins debated over which trail led to Hämsterviel after searching through a jungle, Lilo went with Finder, despite Stitch's protests.
Finder deftly tracked Hämsterviel to Mertle's house, but Lilo began to doubt Finder's accuracy. Earlier, however, Mertle had found Hämsterviel outside a pet shop, mistook him for a talking gerbil, brought him home, and placed him in a cage for show-and-tell. When Mertle tried to cover up for Hämsterviel (after Lilo dropped by to question his presence), Lilo was convinced that Finder had made an error.
After discovering that Finder did uncover Hämsterviel's whereabouts, Stitch burst into Mertle's bedroom that night and attempted to ambush the caged fugitive, but the latter blasted Stitch with a makeshift plasma cannon, knocking him unconscious. The ruckus alerted Mrs. Edmonds, who noticed Stitch and took him to the dog shelter.
The next day, Lilo and Finder arrived at the pound to retrieve Stitch, who revealed to them that Finder had indeed tracked down Hämsterviel. Beforehand, Stitch admitted that he was jealous of Finder and wanted to prove himself to Lilo.
Lilo, Stitch and Finder returned to the Edmonds' home to discover that Gantu had fled with Hämsterviel in his ship, but also kidnapped Mertle. Thus, Stitch decided to team up with Finder to rescue her. Using his helicopter-like flying ability, Finder tracked down Gantu's ship while carrying Stitch, who then disabled the spacecraft, thereby saving Mertle.
Hämsterviel was arrested, but due to Gantu's blunder, the Grand Councilwoman (who had enlisted him to help capture Hämsterviel earlier) did not reinstate him to his former position. However, when Mertle grieved upon discovering her new "pet" was gone, Lilo requested the Grand Councilwoman to let Hämsterviel stay until after show-and-tell at school, albeit in shackles.
Shortly after, Finder was found a one true place operating a beach "Lost and Found" service.
In "Skip", Finder was one of the wanted fugitives who had already been captured in an alternate future where Hämsterviel ruled Earth.
In "Ploot", Finder was one of the second team of experiments (along with Babyfier and Drowsy) formed to try and stop Ploot. However, Ploot was easily able to defeat them, forcing the three experiments to retreat.
In "Snafu", Finder was one of the experiments that joined Lilo and Stitch on a mission to rescue Gantu's captive experiments. Finder helped break into the ship, and after the rescue team successfully freed the captive experiments, he was seen playing with them in Lilo's obstacle course.
The first 624 experiments, including Finder, 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.
Finder participated in the following battle between the experiments and the Leroy clones, but it is unknown what he did.
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.
- Finder is Experiment 158. However, in his debut, he is called 458, most likely due to Jumba's untidy database, but in "Skip", he is correctly referred to as 158.
- If Finder maintained the number he was originally referred to as canon, he would have been the only 4-series experiment to have been featured in Lilo & Stitch: The Series.
- Finder's left ear is inconsistent in his appearances. While he is portrayed as having a notch on the outer rim of his upper right ear (similar to Stitch), his left ear is drawn either with or without a notch around the same relative spot between scenes.
- Finder's pod color is purple.
- Finder is described by the experiment computer screen as, "Experiment 158. Primary function: Finds lost things."
- Finder's ears appear in the online game Jumba's Lab.