Fantastic Four #5: "The Fantast Four Meet... DOCTOR DOOM"|
I saw a comment from magnetic_regina asking whether the Debut of Doom had been posted, and amazingly, it hasn't. Rectified!
"Prisoners of Doctor Doom!" was published July, 1962. After much deliberation, I narrowed down the preview image to just one of the many crackalicious panels:
Tags: char: dr. doom/victor von doom, creator: jack kirby, creator: stan lee, era: silver age, in-joke: science doesn't work that way, theme: origin stories, title: fantastic four