Superboy #104

In a pivotal moment of Kryptonian history, Jor-El unveils the Phantom Zone Projector—a revolutionary step toward justice, designed to imprison criminals without killing them. But when the rejected inventor Gra-Mo turns vengeful, hijacking the planet’s robots to strike back, he becomes the final prisoner sent into space, a cruel irony that sets the stage for the Zone’s dark legacy. Months later, the Phantom Zone’s inmates—among them the menacing Jax-Ur, the enigmatic Dr. Xadu, and the sinister Professor Vakox—attempt to seize control of Jor-El’s mind through telepathy, forcing him to destroy the projector and send it into the void with other forbidden weapons.

In "The Untold Story of the Phantom Zone! Part II: The Kid Who Knocked Out Superboy!", Superboy faces a cunning threat when Gra-Mo and his two unnamed assistants arrive on Earth, aided by the imprisoned Jax-Ur from the Phantom Zone. With a deceptive robot and a twisted scheme to break Superboy’s moral code, they aim to destroy the son of Jor-El—but the truth behind the ruse is harder to see than it first appears.