Dr. Jacques von Hämsterviel is the overall primary villain of the Lilo and Stitch franchise. He is an evil scientist who is Jumba Jookiba's former best friend and partner, Gantu and Rueben's former boss and Stitch and Lilo Pelekai's main enemy.
He was voiced by Jeff Bennett, who also voiced Ozzy in The Land Before Time II: The Great Valley Adventure, Mutt in The Land Before Time III: The Time of the Great Giving and The Land Before Time (TV series), Ichy in The Land Before Time IV: Journey through the Mists and Amos Slade in The Fox and the Hound 2.