Ask, what kind of movie is it? It's a movie based on a comic book. So, to keep the two parts of the 'adjective' or description together, hyphenate comic-book but not movie i.e comic-book movie.
but If I don't join together comic-book" and "movie" with a hyphen, won't "comic book" referring to "opening" instead of "movie?Of course people won't hear the hyphens, GM, but I'd use them in writing: ...the biggest comic-book-movie opening ever.
But If I say "comic book movie opening", isn't that mean "comic and book" are referring to "opening"? , and If I say "comic-book movie opening", doesn't is sound like the "comic-book" is referring to "opening"?My logic (about hyphenating multi-word adjectives) would say "comic-book movie opening".
I would not use a second hyphen ("comic-book-movie opening") because it fails to show that "book" is more closely linked to "comic" than to "movie".
However, all of this may be swept aside by usage:
I did Google searches for the phrase and found only "comic book movie opening": no hyphens.
There are nice, logical rules about hyphenation of multi-word adjectives, but many writers disregard them.