Slugger is an adept baseball player who is actually stronger than he appears to be. He will hit anything that comes his way on instinct due to his programming, but is also one of the least hostile among the other experiments. He seems cautious of people, but gets along quite well with others once he gets to know them.
Experiment 608 was the 608th genetic experiment created by Jumba with Hämsterviel's funding. He was designed to use his bat-like tail to deflect incoming enemy projectiles and swat away balls, toys and fruits thrown over the fence by annoying kids. 608 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 608's pod landing on a baseball field.
608's pod was mixed in with a bunch of softballs. When the team's Little League coach noticed it, he realized it wasn't a softball and tossed it. The pod landed into a drink cooler, the melting ice activating 608, who shivered from the chill.
608 then spotted a woman in a wheelchair throwing a ball for her dog to fetch. Before the dog could retrieve the ball, 608 deflected it with his bat-like tail, much to the dog's puzzlement.
Later, multiple coconuts thrown by Mrs. Hasagawa and deflected by 608 hit Stitch on the head, therefore grabbing his and Lilo's attention. Before they could react, Gantu arrived and grabbed 608, even commenting how weak the latter was as he struggled to get free. Just then, Stitch slammed a crate onto Gantu's head, and 608 got loose from his grasp.
Afterwards, Lilo started talking to 608 and pacified him. When Lilo assured 608 that she and Stitch will keep him out of danger, the former took 608, named Slugger, home and discovered his batting skills. Lilo then decided to put Slugger on her softball team, since Pleakley had jeopardized the previous game with his incompetence, and after Lilo and Mertle wagered a rematch.
Thus, Slugger became Lilo's new softball player against Mertle's team. He did really well during practice until Mertle changed the game to basketball, put Gantu on her team, and even made Slugger be part of the wager. Slugger struggled at basketball because he could only hit things, but the game was still won thanks to Stitch and a very talented Pleakley.
Gantu, being a sore loser, attempted to make off with Slugger, but the latter was saved when Stitch tripped Gantu using one of the basketball goals. Enraged, Gantu ripped out the other basketball pole and tried to retaliate. However, he was thwarted by Stitch, who then let Slugger use the pole to whack Gantu over a vast distance.
Slugger was later found a one true place as the new hitter for the Little League softball team, whose coach (the same one who activated Slugger earlier) wasn't a very good hitter himself. With Slugger coaching Little League, the team would eventually become first place.
Slugger reappeared in "Glitch", where a baseball pitching machine went out of control while he was practicing his batting skills. Regardless, Slugger deflected every ball the machine threw at him, along with 223's pod.
Slugger was seen early in the movie coaching Little League softball with his batting skills as Lilo was making her rounds with Scrump to make sure all the experiments were happy in the one true place they belonged.
Later, the first 624 experiments, including Slugger, 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.
Slugger participated in the following battle between the experiments and the Leroy clones by deflecting Leroys' plasma projectiles back at them. He also carried off a couple of Leroys with his bat-like tail.
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.
- Despite Gantu claiming Slugger to be weak, he was able to grasp a basketball pole and whack Gantu over a vast distance without any struggle, and another time he suspended Stitch in mid-flight, again without any struggle.
- Slugger's pod color is blue.
- Slugger is described by the experiment computer screen as, "Experiment 608. Primary function: Deflection of incoming enemy projectiles."