Fantastic Four #26
Story by Stan Lee with art by Jack Kirby and inks by George Bell. Guest-starring the Avengers and the Hulk. The first family of Marvel Comics, the Fantastic Four, meet Earth's Mightiest Heroes, the Avengers, for the first time in a mad dash to stop the rampaging Hulk. Ben Grimm, the Thing, tries valiantly to halt the gamma-powered brute but finds he can't do it by himself. Now, Thor, Giant-Man, Captain America, the Wasp and Iron Man think it's time "The Avengers Take Over!"
Mr. Fantastic is laid up in the hospital with a dangerous fever. The Human Torch recuperates nearby, bandaged from his last tussle with the Hulk. And as the Invisible Girl waits and prays, the Thing fights on alone. But not for long. Enter the Avengers, who wish nothing more than to curtail their former member, the monster that was Bruce Banner. But as these things often unfold, the FF end up clashing with the Avengers as New York's streets become crowded with costumed heroes. See Mr. Fantastic rope up Iron Man. The Invisible Girl traps Giant-Man in her force field. Thor pummels the Thing accidently. Can these two super-teams overcome their differences in time to save a city?