My string of posts about 1967 wouldn't be complete without mentioning Fantastic Four King-Size Special #5 (a.k.a. Annual #5).
Promising to announce the biggest surprise of the year, the main story began with Susan Richards fainting—raising concern from her friends and family. The suspense ended later that issue with news that Sue was going to have a baby. Born in King-Size Special #6 (Nov. 1968), the son of the Invisible Girl and Mr. Fantastic came to signify how much time had passed in the lives of Marvel characters from that point forward.
In less surprising news, King-Size Special #5 also included a backup story starring the Silver Surfer.