The extra-terrestrial race known as the Sagittarians had long ago pledged to serve the Galaxy Master
in order to prevent him from destroying their own planet and race. To this end, they designed a machine known as the Planet-Destroyer capable of wreaking havoc across an entire planet. They would place this Planet-Destroyer on other planets to render them unable to resist the Galaxy Master, to make its destruction of them easier.
An undisclosed time period ago (likely centuries), the Sagittarians placed a Planet-Destroyer on Earth, hiding it in a cave in the Savage Land
. They then placed an immense robot, Umbu, on a pedestal in the village of a tribe of Swamp Men, warning them that if the Glowing Machine was tampered with, Umbu would come to life and destroy whoever was responsible. The Swamp Men grew to worship the inanimate form of Umbu, and made an effort to prevent others from approaching the cave containing the Glowing Machine. The Swamp Men also would periodically offer a human sacrifice to keep their god, Umbu, appeased.
The Hulk was then confronted by Umbu, who had been activated after Banner tampered with the Planet-Destroyer. The Hulk attacked Umbu, but after a short battle, he was defeated by a gas from Umbu, which rendered him unconscious. The Hulk reverted to Banner, whom Umbu failed to recognize as the same being. Banner quickly ran back to the cave and worked to decipher the circuits as Umbu attempted to stop him. Banner succeeded in removing the machine's Master Control Unit, which rendered Umbu inert as well, causing it to collapse.
Umbu was created by Stan Lee and Herb Trimpe in 1968 and first appeared in The Incredible Hulk # 110.
Powers & Abilities
Umbu was an immense, approximately 50' tall robot. It possessed Class 100 strength, and self-repair circuits which enabled it to rebuild damaged portions of itself in seconds. It could fire powerful energy blasts from its staff capable of stunning the Hulk or incinerating an entire tree. It could release a potent knock-out gas from its mouth. Umbu was dependent on the Planet-Destroyer's Master Control Unit for activity. When it was deactivated, Umbu was as well.