Experiment 285 was the 285th genetic experiment created by Jumba with Hämsterviel's funding. He was designed to shoot a green beam that causes people to become extremely lazy or technology to stop working. 285 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 285's pod landing in some bushes near the Pelekais' house.
Meanwhile, Lilo and Stitch, a local and her alien friend, have made a mess trying to create a new recipe. Lilo's older sister, Nani, orders them to clean it up, and then leaves for work (however, while driving through a puddle, Experiment 285's pod was activated). Instead, they try to make Pleakley, another alien with a love of cleaning, do it. However, after seeing how huge the mess is, Pleakley faints.
Sometime after, Stitch wanders outside and does nothing except lie in a hammock. Then Pleakley is zapped by the same unknown energy that got Stitch, causing him to laze about in a similar fashion. The same goes for another alien named Jumba, who just arrived.
It turns out the culprit is Experiment 285, or Lax, an alien experiment with an antenna-like appendage that is designed to cause people to be very relaxed and lazy. Lilo and a lazy Stitch chase after him, but instead find Spinelli running towards the pool of a hotel, followed closely by the rest of the Recess Gang. Lilo follows as well, but then Mikey and Vince (though at separate times) are zapped by Lax. Lilo explains everything to T.J., and they then try to capture Lax, but they fail and he escapes.
Meanwhile, another alien named Gantu is made to follow a satellite's directions to find Lax for the evil Hämsterviel. Lilo and four of the Recess characters, Gus, T.J., Gretchen, and Spinelli, catch up to Lax at an observatory. T.J. and Spinelli try to get Lax themselves, but they too get zapped. Just then, Gretchen finds the new "planet" that she discovers, but Lilo finds out it's only a satellite being used by Hämsterviel (the same one Gantu uses).
Gretchen's Galileo computer is zapped; however, Gretchen gets the idea to use the telescope to zap the satellite. While most of the Recess Gang distract Lax by hitting golf balls at him, Gretchen is zapped, but she still works on the plan; apparently, she finds work relaxing. Gus gets chased by Lax, but Lilo distracts Lax just in time for Stitch to pummel him. Lilo, Gretchen, and Gus then put their plan into action, and the satellite ends up destroyed. Gantu confronts them, but Lax zaps him, thus ending the threat.
The Recess Gang eventually goes back to normal, and Lax finds a hobby in zapping stressed and unpleasant tourists at the airport. Then Spinelli wonders where Finster is. It turns out Finster has never left the spa.
The first 624 experiments, including Lax, 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.
Lax 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 ʻOe", which caused the Leroy army to shut down due to the original Leroy's fail-safe.
- Lilo and Gus are the only main characters to not get zapped by Lax.
- There are a couple of moments between T.J. and Spinelli, like when he asked her to help him out with distracting the experiment Lax. Also, when the six kids plus Lilo and Stitch were all at the observatory, right before the two of them both get zapped by Lax, Spinelli is seen quickly taking T.J. by the hand and then running up together to the rooftop of the building. After that, they are both seen goofing off together on the beach, while under Lax's spell.
- Lax's pod color is green.
- Lax is one of the few experiments to not appear in the group photo at the end of Leroy & Stitch.