It's likely you are referring to the Fantastic Four comic book series. The number 3 refers to a specific issue of the comic.
It seems you are asking about a movie adaptation of that issue, but that doesn't exist.
There have been several Fantastic Four movies:
* Fantastic Four (2005)
* Fantastic Four: Rise of the Silver Surfer (2007)
* Fantastic Four (2015)
None of these movies are specifically based on issue #3 of the comic.
If you are looking for a specific Fantastic Four movie, please provide more details about what you are looking for.