Caught a video yesterday from a guy who was just amazed the upcoming Fantastic Four: First Steps tie-in comic was developed as if it were an in-universe comic. He was totally mind-blown.
Don't get me wrong, I like the idea. But I liked it, too, when Marvel did it 25 years ago with an entire line of comics. And when Alan Moore did it before that with The Black Freighter stories in Watchmen. And before that when there was an actual Spinal Tap album to promote the movie.
This is hardly new.