A four-armed, blue-skinned extra-terrestrial rival of Brainiac who, in October 1966, uses his 20th-level intellect to defeat Brainiac—who has only a 12th level intellect—and steals the android's force field as part of his plot against Superman, against whom he seeks revenge for past defeats. Grax tells Brainiac, "Only last month, he crushed my army of robot invaders...before that, he had beaten my disc machines when they stole Venusian radonite".
Grax then uses a rocket to attach to Superman a bomb capable of destroying the earth, warning the Man of Steel that if he removes the bomb it will explode. When Superman tries to leave Earth for its own safety he finds that he cannot, for Grax has surrounded the planter with Brainiac's force field which he has reinforced with red-sun energy. Grax tells Superman that the bomb will soon destroy the earth and there is only one way to can prevent this.
However, Brainiac, seeking his own revenge against Grax, contacts Superman and tells him to construct an enormous magnet that traps Grax's ship against the force field. Positioning himself just inside the shield next to Grax's ship, Superman warns Grax that the bomb only has one minute left on its timer. Realizing that the shield will not be strong enough to protect him from the blast at such close range, Grax begins to instruct Superman on how to deactivate the bomb. However, with only five seconds left to detonation, it is too late. In a panic, Grax creates a hole in the force field to allow Superman to enter his ship hoping that he can still deactivate the bomb himself.
The bomb explodes. Superman's invulnerable body is unaffected and the combined protective power of the force shield around Grax's ship and the one around Earth protect it from the blast. Grax escapes destruction by transforming himself into a phantom at the last moment. Superman then returns Brainiac's force field to him saying that he owes it to him (Act No. 342/1: "The Super-Human Bomb!").
Other Canonical Appearances:
- Act No. 417, Oct 1972: "The Conspiracy of the Crime-Lords!"
- Act No. 418, Nov 1972: "The Attack of the Phantom Super-Foes!"