"The Monster and the Man-Beast!"
After destroying the Mandarin's castle, the Hulk blusters about Communist China, plagued by the military. Fed up with the pursuit, the Hulk latches onto a ballistic missile test for a ride to a better place. His actions cause the missile to crash land in the Antarctic, depositing the Hulk in the Savage Land, where he transforms back to Bruce Banner. He is found and captured by the Savage Land's Swamp Men, but rescued by Ka-Zar and Zabu. Ka-Zar shows a mysterious machine to Banner which was installed by an unknown person. Banner divines that it is designed to alter the Earths rotational axis, which would result in world-wide catastrophe. Whoever installed the machine has the allegiance of the Swamp Men, who attack, changing Banner back to the Hulk, who has no concept of the machine's danger, nor that Ka-Zar is his ally. 20 pages.
Reprinted in Marvel Super-Heroes (1967) #63.