The Fantastic Four: First Steps follows Marvel's First Family during a pivotal time in their lives: The pregnancy and birth of Reed and Sue's baby son, Franklin. That also coincided with the most significant challenge the Four had yet faced: Their planet served up as a snack for the intimidating Galactus.

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,