Note: Be aware there are spoilers for “The Fantastic Four: First Steps” in the article below.

Here are all the movies and shows Marvel has left to release before its next major team-up film, "Avengers: Doomsday"

But that all changes in the movie's post-credits scene, when the vibe shifts and suddenly there's a metal-masked stranger hanging out in the living room of the Baxter Building. If you've seen The Fantastic Four: First Steps and need some Reed Richards–level tutoring to figure out just what the heck is going on,