Tales of Suspense Vol.1 #80
Captain America rescues a pilot whose plane was shot out of the sky, only to discover he's a member of A.I.M., and he tells Cap about A.I.M.'s "supreme achievement" - The Cosmic Cube - which has been stolen by its "keeper," who's taking it to his new master... The Red Skull.
Printed: Aug 1966
Writers: Stan Lee and Jack Kirby
Art: Gene Colan, Jack Kirby, Don Heck, and Jack Abel [as Gary Michaels]
Cover: Jack Kirby and Don Heck