Gus the Second, A.K.A. Experiment 398, is an illegal genetic experiment created by Jumba Jookiba. He is designed to cause uncontrollable thirst (does so by shooting a beam at his targets that makes them believe they are thirsty even if they are not, thus causing over hydration). His one true place is refilling drink machines.
Experiment 398 was the 398th genetic experiment created by Jumba with Hämsterviel's funding. He was designed to cause uncontrollable thirst.
398 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 the unknown point, he was activated, captured, tamed and named Gus the Second.
All 624 experiments, including Gus the Second, were round 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 Gus the Second 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 Oe, which caused the Leroy army to shut down due to the original Leroy's failsafe.
- Gus the Second is named the Second, despite being a lower number than Gus (526). This is assumed to be because Lilo found him after 526.
- Gus the Second is described by the experiment computer screen that says "Experiment 398 Primary function: Eat crops".