Designated Experiment 625, Reuben is Dr. Jumba Jookiba's genetic creation, a prototype for Experiment 626 (Stitch) deemed a failure due to inherent laziness and cowardice. Despite possessing all of Stitch's formidable physical capabilities—super strength, wall-scaling, rapid cognition, night vision, and multi-limb generation—he rarely exerts himself, preferring minimal effort. His singular passion is crafting and consuming sandwiches, a skill he masters. Activated by Captain Gantu and Dr. Hämsterviel in *Stitch! The Movie* to torture Jumba, Reuben ignored his mission to make sandwiches, revealing his passive core. Stranded on Earth with Gantu after their ship crashed, he became Gantu's reluctant sidekick during *Lilo & Stitch: The Series*. He often mocked Gantu's incompetence but secretly viewed him as a best friend, occasionally leveraging his knowledge as Jumba's former lab assistant to provide tactical intel on other experiments. His intelligence and familiarity with all experiments made him a strategic asset, though his loyalty wavered; he sometimes aided Lilo and Stitch against Gantu for self-preservation. A pivotal shift occurred in *Leroy & Stitch* when Gantu abandoned him on Earth. Hurt and embittered, Reuben converted Gantu's deserted ship into a sandwich shop. Persuaded by Lilo Pelekai to help rescue Stitch, he accepted the name "Reuben" after rejecting other suggestions. This marked his first significant power use: repairing the ship and traveling to Turo to warn the Galactic Alliance of Hämsterviel's takeover. Initially resistant, Reuben ultimately helped reform Gantu and joined the battle against the Leroy army, using unconventional tactics like distracting enemies with sandwiches. For his actions, he was appointed Gantu's galley officer in the reformed Galactic Federation. In the *Stitch!* anime continuity, Reuben continued working with Gantu and Hämsterviel after their discharge. During their time on Izayoi Island, a bread shortage led him to discover onigiri (rice balls) through Yuna's grandmother, temporarily shifting his culinary focus before reverting to sandwiches. Hämsterviel once modified him, enhancing his aggression and granting a "bad boy" persona that allowed him to defeat Stitch and briefly attract Angel. This alteration reversed when Reuben witnessed incorrect sandwich preparation, restoring his original demeanor. Reuben appeared in the special *Stitch and the Planet of Sand*, the anime finale, and *Stitch! Perfect Memory*, culminating in imprisonment alongside Hämsterviel, Gantu, and Delia. His design remains consistent: golden-yellow, koala-like, with floppy ears, three antennae, buck teeth, and a slightly shorter stature than Stitch. Reuben harbors a secret familial bond with Stitch, considering him a brother despite their rivalry for Angel's affection. His complex relationship with Gantu blends sarcasm with underlying loyalty, and his fearlessness toward Hämsterviel contrasts with Gantu's subservience. Moments of vulnerability—jealousy over Gantu's attention to other experiments or loneliness after abandonment—add depth to his apathetic exterior. Reuben made a cameo in the 2025 live-action *Lilo & Stitch* film, appearing in Jumba's visual aid labeled "625" during a demonstration of Stitch's potential modifications.