Fantastic Four (1961) #76

"Stranded in Sub-Atomica!"

The Fantastic Four enter the Microverse to find the Silver Surfer. They try to force him to come back with him, but the Surfer overpowers them. They are then attacked by the Psycho-Man's Indestructible One. Delayed by this new menace, they start to worry about Galactus destroying the Earth. Hearing this, the Surfer makes the Indestructible One disappear and agrees to confront Galactus.