Action Comics #400

My Son... Is He Man Or Beast?Yes, Superman! You created this grotesque creature... Now, as its guardian, fate decrees you must treat it like your own flesh and blood... but before you accept the eerie challenge, ask yourself one question -- My Son... Is He Man Or Beast?Duel of Doom!Kandor... once a giant metropolis on Krypton, Superman's native planet, and now a mini-city coveted by the evil computer, Brainiac! Don't panic! The super-due will save it! But, ironically, deep within the bottled city, their teamwork only inspires a desperate Duel of Doom!My Son... Is He Man or beast? -- When radio-biologist Jan Nagy dies, he makes Superman the guardian of his son Gregor, but Gregor is violently opposed to this. Some years in the past, when Jan was working on a new element called metamorphon,...