10 Comic Book Movies You Didn't Know Were Linked
9. Fantastic Four's Extended Cut Confirms A Shared Universe With Fox's X-Men
2005's largely forgettable Fantastic Four movie does nevertheless feature a single seconds-long moment in its Extended Cut - yes, it has an Extended Cut - which heavily implies, if not confirms, that the Fantastic Four films exist in the same universe as the X-Men franchise (both being owned by Fox...at the time).
When Reed Richards (Ioan Gruffudd) is explaining to Sue Storm (Jessica Alba) that he thought she wanted a stronger man, he uses his body-moulding abilities to transform his face into that of Wolverine (Hugh Jackman). A crude, early-2000s CGI approximation of it, anyway.
The point isn't the trash VFX, though - it's that, with this scene, Fox effectively confirmed that not only do the X-Men and the Fantastic Four share this universe, but that the Four are aware of the X-Men, and likely the other way around, too.
Of course, these goofball movies never took themselves seriously enough to actually consider doing a legit crossover, but all the same, the link between them is there - even if most audiences never bothered to watch the Extended Cut and see it for themselves.