Adventure Comics #290

In "The Secret of the Seventh Super-Hero!" from Adventure Comics #290, a mysterious impostor claiming to be Sun Boy arrives in Smallville seeking Superboy’s help to build a powerful super-weapon, while a real threat emerges from a different direction—Tom Tanner, a runaway from reform school, has taken on Clark Kent’s identity and is using it to his advantage.

In "The Invasion of the Bizarro World!", the Bizarros cheer as their world is overrun by strange, animated blue kryptonite creatures—until the invaders try to reshape their round planet into a sphere, sparking chaos. With regular lead suits useless against the radiation, the Bizarros must rely on flawed, imperfect duplicates to survive.