320 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 some point, 320 was presumably activated, captured, and named Cloudy.
Later, the first 624 experiments, including Cloudy, 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.
It is unknown whether or not Cloudy 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.
- Cloudy is the only known experiment associated with Mrs. Hasagawa that did not debut in the episode "Mrs. Hasagawa's Cats".
- While it is confirmed that Cloudy works with Mrs. Hasagawa, it remains unconfirmed whether Cloudy returns home with her from the fruit stand.
- Cloudy is one of three known limbless experiments, the other two being Slimy and Zap.
- Cloudy, Zap, Remmy, Welco, and Shrink are the only known experiments that are always seen levitating.