Dr. Jacques Von Hamster-vile (voiced by Jeff Bennett in the original series and Kirk Thornton in the anime series), is the main villain in Lilo and Stitch, Stitch: The Movie, and Leroy and Stitch, except in Stitch Has a Glitch where he was remains absent, along with Captain Gantu and Reuben. Hamster-vile is an evil mad scientist, who is secretly the infamous Japanese American criminal known as Jesse Victor Hara. Hamster-vile has the boyfriend of his associate Eleanor Miller (Amy Poehler), named Theodore Seville (Jesse McCartney), kidnapped by his henchmen Reuben (voiced by Rob Paulsen in the original series and Dave Wittenberg in the anime series), so he can hold him for ransom, whilst pretending to help Eleanor Miller to find him as he awaits for the ransom money. Simon Seville (Matthew Gray Gubler) and his older brother Alvin (Justin Long) are assigned the task of locating and rescuing their younger brother Theodore Seville, as well as discovering the identities of his attackers.
Hamster-vile appears at the Naha Convention Center where an art exhibition is taking place, and he is seen making a speech with Eleanor Miller at his side, along with her two older sisters Brittany (Christina Applegate) and Jeanette (Anna Faris). Both Alvin and Simon arrives and Hamster-vile's cover is soon exposed; and he reveals that Theodore Seville is being held hostage in a while Honda van outside with an explosive black leather jacket attached to him. Alvin goes to rescue Theodore and dares Hamster-vile to detonate the explosive black leather jacket in front of him and Reuben (who is also present). Hamster-vile escapes into the rafters and Simon pursues him, having successfully removed the explosive black leather jacket from his younger brother Theodore, while Alvin, Brittany, and Jeanette deals with Hamster-vile's henchmen Reuben and finally kills him by giving him a gunshot wound. Enraged, Hamster-vile attacks and hits Simon with his black leather suitcase full of ransom money, but accidentally topples over the edge, and is left hanging onto Simon's explosive black leather jacket. As he struggles to keep his grips, the explosive black leather jacket rips in half under his weight and sends Hamster-vile plunging to his death onto the roof of a parked black Toyota van.