The Incredible Hulk #109

The Hulk stops a deadly Chinese missile from being launched but the huge detonation drops him into the Savage Land where he transforms back into Bruce Banner. Being rescued by Ka-Zar from the Swamp Men, the jungle lord asks for Banner's help in deactivating a mysterious machine that is making weather all over the world to go wild and will eventually lead to the destruction of Earth. The Swamp Men renew their attack and Banner becomes the Hulk to face the threat, totally forgetting about the deadly machine he was supposed to deactivate.