Marvel Comics - The Fantastic Four first issue
Together for the first time
Wait, they used to have separate comics?
IIRC Reed, or an un-named scientist who looked exactly like Reed, first appeared in one of Marvel's monster comics. Might have just been Kirby design aesthetic at work.
No. Don't over analyse. Otherwise you'd have to explain how Mr. Fantastic got tied up in the first place...
Or how being invisible can help in this situation
It's the first issue, so first time period, together or separate.
"The three of you can't do it alone!"