Professor Waltom is tall, bald, dark blue, reptilian koala/bear-like experiment with a crocodile-like teeth, and a roundly body reminiscent of Batman supervillain Penguin who is obese, humanoid version of Stitch with the same abilities, but he is villain more intelligient than Stitch. He wears a hat, monocle, and a dark gray pinstripe suit with a military badge. He is the main antagonist of two films. He is a evil scientist and galaxy conqueror who carries a steel tomahawk axe formed as pimp cane, a Bergmann-Bayard pistol, a dagger, a plasma gun, a sickle, and a military crossbow, and flies in a flying fortress, later in a balloon aircraft and a heliocoptor. His minions were a gas masked experiments, and a tank-like experiments. His personality is similar to Clavius, Dr. Phillium Benedict, and Lots-o'-Huggin' Bear. He speaks English with a hint of British/German accent.
He was created by Jumba Jookiba who was his former friend and creator in the laboratory together, but there Waltom finds out that he is betrayed and droved underground by Jumba and the Grand Councilwoman in the Galactic Alliance, so he will have his revenge.
Living in his fortress, Waltom planned to revenge on Jumba who was lived on Earth, so he could conquer Saudi Arabia. His pet Vultar, a vulture who is turning into cyborg, and his lieutenant, Bobert Cancer, who was created by Jumba, and was Angel's friend.
Living in the mountain on Cuba in the second film, Waltom planned to destroy Stitch, and Jumba, so he could enter the island, and get the Core of Forbidden Spirits, which was a crystal ball containing magical and super powers - the power to create, change, transform, invisible, levitate, super strength, and destroy.
So Waltom and his minions disguised as a clowns riding their balloon aircraft, kidnapped Zuruko, who is Jumba's girlfriend, and held her hostage so Jumba would come to him. When Jumba sets out to rescue Zuroko, Waltom and his minions sneak into Yuna's house where they tie and gag Angel up and take her to the heliocoptor.
Professor Waltom was able to get the Core of Forbidden Spirits and absorb its power. Stitch fought Waltom , who gained the advantage by his magical and super powers and his tomahawk axe (formed as a pimp cane), but Iago jumped on him to distract him at the last second, and Waltom killed him (from which he was revived by the Spiritual Stone at the end of the film).
Then Stitch grabbed the orb, which would explode if it fell to the ground or if blasted by the power to destroy. As he and the others made their escape in Waltom's hot air balloon, Waltom jumped onto it and tried to attack Stitch and take the orb back, but Stitch knocked him over the edge onto the dock, accidentally sending the orb falling as well. When the orb hit the ground, it exploded and caused the mountain - really a dormant volcano - to erupt. Everyone was able to escape, so as Waltom, Vultar and his minions, who ride in their heliocoptor and manage to be free.